Overview
In 2025, a long-simmering territorial dispute along the 817 km Thailand–Cambodia border reignited into the region’s most serious interstate conflict in years. A fatal clash on May 28 that killed a Cambodian soldier in a disputed area near Preah Vihear was followed by landmine incidents and escalating skirmishes, culminating in a five-day war in July that killed at least 48 people and displaced about 300,000 civilians before a ceasefire was brokered by U.S. President Donald Trump, with Malaysian Prime Minister Anwar Ibrahim mediating under ASEAN’s umbrella.
The Trump–Anwar peace initiative produced a July truce and an expanded ceasefire agreement signed in Kuala Lumpur in October, under which both sides began withdrawing heavy weapons and de‑mining contested areas. But a new landmine blast that maimed a Thai soldier in November led Bangkok to suspend the deal, and on December 8 Thailand launched airstrikes on Cambodian positions after fresh clashes, evacuating more than 385,000 people from border districts. Cambodia denies planting new mines or firing first, while influential former leader Hun Sen calls Thailand the aggressor yet urges restraint, underscoring the risk that renewed hostilities could unravel ASEAN’s non‑war tradition and draw in outside powers.
Key Indicators
People Involved
Organizations Involved
Thailand’s central government, led in late 2025 by Prime Minister Anutin Charnvirakul, directs national security, foreign policy, and military operations along the Cambodian border.
Cambodia’s central government, led by Prime Minister Hun Manet and heavily influenced by former premier Hun Sen, manages military deployments and diplomatic responses along the Thai border.
Thailand’s army and air force are centrally involved in artillery exchanges, border patrols, and the December 8 air campaign against Cambodian targets.
Cambodia’s military maintains positions in disputed border zones and has engaged in exchanges of fire with Thai forces while managing evacuations in provinces like Oddar Meanchey.
ASEAN is the primary regional forum for political and security cooperation in Southeast Asia, including mechanisms for managing interstate disputes between member states.
The U.S. government has played an unusually direct role in brokering ceasefires between Thailand and Cambodia, conditioning trade negotiations on an end to fighting.
CMAA oversees demining activities in Cambodia and has been central to arguments about the age and origin of landmines injuring Thai soldiers.
Timeline
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Mass evacuations on both sides of the border
Humanitarian ImpactThai authorities evacuate more than 385,000 civilians from four border districts, housing over 35,000 in temporary shelters, while officials in Cambodia’s Oddar Meanchey province report evacuating more than 1,100 families as artillery fire resumes. Rights groups and local witnesses describe damage near civilian areas and widespread fear.
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Thailand launches airstrikes along disputed border
Military ActionThailand conducts airstrikes into Cambodian territory after reporting that a Thai soldier was killed and others wounded in clashes, and accusing Cambodia of mobilising heavy weapons and firing rockets toward Thai areas. The air force says it targeted Cambodian military facilities. Cambodia claims Thailand launched dawn attacks on its positions and insists its forces have not retaliated.
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Deadly exchange of fire resumes
Military IncidentAt least one person is killed in Cambodia as both neighbours accuse each other of opening fire along the border, indicating that the ceasefire is rapidly unravelling just weeks after the enhanced deal.
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Thailand suspends implementation of ceasefire pact
Diplomatic MoveThailand announces it is halting implementation of the ceasefire agreement with Cambodia after the November 10 mine blast, describing it as the biggest test of the Trump‑brokered truce. Bangkok files a formal protest and says it will explain its decision to Washington and Kuala Lumpur.
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New landmine blast maims Thai soldiers, testing the truce
Military IncidentA PMN‑2 mine explosion injures four Thai soldiers, one losing a foot, near the disputed border. Thailand accuses Cambodia of laying new mines in violation of the ceasefire, while Phnom Penh denies this and blames legacy contamination.
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Heavy‑weapons withdrawal and de‑mining begin
ImplementationBoth governments announce they have started pulling back rocket systems and other heavy weapons from the border and begun de‑mining work in multiple sites, in line with the October agreement. Thailand says it will not release prisoners or fully reopen border checkpoints until it is satisfied with Cambodia’s compliance.
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Enhanced ceasefire and peace agreement signed in Kuala Lumpur
CeasefireThe leaders of Thailand and Cambodia sign an expanded ceasefire agreement at an ASEAN summit in Kuala Lumpur, witnessed by U.S. President Donald Trump. The deal covers phased withdrawal of heavy weapons, de‑mining, and the return of 18 Cambodian prisoners of war, and earns Trump a Nobel Peace Prize nomination from Cambodian figures.
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Experts say landmines likely newly laid
Public RevelationA Reuters investigation, drawing on visual evidence and assessments from four independent landmine experts, concludes that PMN‑2 mines linked to July border blasts appear to have been in the ground for only a few months. Cambodia’s mine authority disputes this, highlighting the difficulty of judging age from photographs alone.
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Thai military showcases mine clearance to media
InvestigationThailand’s Mine Action Centre demonstrates the detonation of PMN‑2 mines during a media visit, sharing imagery later assessed by independent experts as showing relatively new mines. Analysts say the devices appear freshly laid but cannot attribute responsibility.
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Initial ceasefire signed in Putrajaya
CeasefireUnder Malaysian and U.S. auspices, Thai and Cambodian leaders sign a ceasefire agreement in Putrajaya, pledging to end active hostilities, resume direct communications, and establish mechanisms to implement the truce.
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Trump threatens tariffs to force ceasefire talks
Foreign MediationU.S. President Donald Trump announces he has called the leaders of Thailand and Cambodia, warning he will suspend trade deals and impose tariffs of up to the mid‑30 percent range if fighting continues. Both sides signal readiness to discuss a ceasefire under U.S. and Malaysian mediation.
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Five-day war erupts along the border
Military ActionArmed clashes break out along multiple stretches of the frontier. Thailand and Cambodia trade artillery, rockets, and small‑arms fire; Thailand deploys F‑16s to bomb a Cambodian military position. Over the following days, at least 48 people are killed and some 300,000 displaced, with rights groups warning of attacks near civilian infrastructure.
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Further landmine incidents and diplomatic downgrades
DiplomacyAnother mine incident occurs along the border, and Thailand recalls its ambassador from Phnom Penh and announces the expulsion of Cambodia’s ambassador. The moves mark a sharp diplomatic escalation ahead of open fighting.
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Landmine blast injures Thai soldiers, sparking accusations
Military IncidentA landmine explosion near the border seriously injures Thai soldiers; Bangkok later identifies the device as a Soviet‑origin PMN‑2 and claims the mine was freshly laid. Cambodia argues that contamination from past wars is to blame, and CMAA calls for impartial investigation.
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Sides agree to return to prior positions but tighten border controls
De-escalationFollowing diplomatic contacts, Thailand and Cambodia agree to return troops to previous positions after the May clash. At the same time, Thailand places control of border crossings under army authority and shortens opening hours at several points, citing threats to sovereignty.
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First fatal firefight at disputed border position
Military IncidentCambodia reports that one of its soldiers is killed in a brief exchange of fire with Thai troops in a disputed region between Preah Vihear province and Thailand’s Ubon Ratchathani. Both sides accuse the other of shooting first; Thai officials say they suffered no casualties. Cambodian and Thai leaders speak by phone to urge calm, but tensions remain high.
Scenarios
Renewed ceasefire under ASEAN and U.S. pressure restores a fragile calm
Discussed by: Reuters analyses, regional diplomats quoted in Malaysian and Singaporean press, and ASEAN statements
In this scenario, shock at the use of airstrikes between ASEAN members prompts an all‑out diplomatic push. Malaysia, as ASEAN chair, convenes an emergency summit with strong backing from the United States and possibly China. Thailand halts further air operations in exchange for Cambodian commitments on mine‑clearance transparency and limited pullbacks from key contested positions. A revised ceasefire would likely include third‑party verification of mine incidents, more robust communication hotlines, and clearer rules on heavy‑weapons deployments. The fighting would subside, but underlying demarcation disputes and mutual distrust would remain unresolved, leaving the region with a brittle peace similar to post‑July conditions.
Protracted low‑intensity conflict with recurring flare‑ups and stalled demarcation
Discussed by: Security analysts in Reuters explainers and commentary, regional think‑tank commentary
Here, neither side is willing to make the concessions needed for a durable settlement, and domestic politics in both Thailand and Cambodia reward nationalist posturing. After a period of reduced intensity, sporadic artillery exchanges, sniper fire, and mine incidents continue along the frontier. Evacuations and returns become cyclical, causing long‑term economic damage and humanitarian strain. ASEAN discourages open war but struggles to move the parties toward a final border demarcation or joint de‑mining plan. This scenario resembles the 2008–2011 Preah Vihear period, with intermittent clashes that occasionally spike but stop short of full‑scale war.
Major escalation into a broader regional crisis
Discussed by: More cautionary analyses in international media drawing parallels to past India–Pakistan air confrontations
If a high‑casualty incident occurs — such as a rocket strike on a densely populated town or a downed aircraft over civilian areas — political leaders could feel compelled to escalate rather than compromise. Thailand might expand air and artillery strikes deeper into Cambodian territory, while Cambodia could respond with longer‑range rockets or attacks on economic infrastructure. Refugee flows could surge into Laos and Vietnam, prompting calls for UN Security Council involvement. The presence of U.S. and Chinese interests, and Trump’s personal stake in the earlier ceasefire, could internationalize the crisis, testing ASEAN’s cohesion and potentially reshaping security alignments in mainland Southeast Asia.
Conflict drives domestic political shifts in one or both countries
Discussed by: Commentary in regional outlets and international coverage of Thai and Cambodian domestic politics
Sustained or unpopular conflict could trigger political repercussions. In Thailand, high casualties or perceived mishandling of evacuations might fuel criticism of Anutin’s government from opposition parties or within the military, especially given the leadership change earlier in the year. In Cambodia, if economic strains and displacement mount, Hun Manet’s authority — and the legitimacy of the dynastic handover from Hun Sen — could be questioned by opposition figures or within the ruling party. Either scenario could alter negotiating positions and make compromise either easier (if new leaders seek a reset) or harder (if hawks gain influence).
Structured border settlement and joint de‑mining with international backing
Discussed by: Optimistic strands in ASEAN diplomatic commentary and some expert proposals
A less likely but transformative outcome would see both sides accept that bilateral talks alone cannot resolve the century‑old dispute, leading to a structured process involving technical border commissions, third‑party mapping assistance, and robust joint de‑mining. This could be anchored in ASEAN mechanisms and potentially draw on UN or International Court of Justice expertise, echoing the role the Court played over Preah Vihear. Implementation would be phased and politically sensitive but could gradually reduce military incidents and allow border communities to recover.
Historical Context
2008–2011 Preah Vihear Temple Border Clashes
2008–2011What Happened
After the Preah Vihear temple on the Thai–Cambodian border was listed as a UNESCO World Heritage Site in 2008, long‑standing disagreements over 4.6 square kilometres of surrounding land escalated into repeated military clashes. Thai and Cambodian troops exchanged rocket, artillery, and small‑arms fire near the temple, causing casualties on both sides and damage to the ancient structure. Fighting flared repeatedly in 2010–2011, prompting Cambodia to seek UN Security Council involvement and to call for an international buffer zone, while Thailand resisted external mediation.
Outcome
Short term: Dozens were killed over several years, thousands displaced, and nationalist sentiments surged in both countries, but large‑scale war was avoided.
Long term: In 2013 the International Court of Justice clarified that Cambodia had sovereignty over the temple and much of the surrounding area, reducing but not eliminating tensions; demarcation of the wider border remained incomplete.
Why It's Relevant
The Preah Vihear clashes show how historical grievances and domestic politics can turn small areas of disputed territory into recurring flashpoints. The current 2025 fighting is unfolding in similar locations and with some of the same actors, including Hun Sen, reinforcing fears that, without clear demarcation and credible monitoring, ceasefires will remain fragile.
Cambodia’s Civil Wars and the Landmine Legacy
1970s–1990s and aftermathWhat Happened
Decades of conflict in Cambodia, including the Khmer Rouge era and subsequent civil wars, left the country among the most heavily mined in the world. A mine‑contaminated belt more than 1,000 km long stretches along much of the Thai–Cambodian border. Large‑scale demining began after a 1991 peace accord, but PMN‑2 and other mines remain a persistent hazard despite the clearance of thousands of square kilometres and the destruction of stockpiles under the Ottawa Convention.
Outcome
Short term: Landmines continued to kill and injure civilians and soldiers for decades, constraining agriculture and development along the frontier.
Long term: International funding and national programs significantly reduced contamination, but sporadic incidents still occur, and the 2025 dispute over whether new mines are being laid shows how this legacy can fuel new conflicts.
Why It's Relevant
The 2025 crisis hinges in part on whether recent blasts are caused by newly planted mines or old ordnance. Cambodia’s mine legacy complicates attribution, allows both sides to construct competing narratives, and makes neutral verification central to any sustainable settlement.
2019 Balakot Airstrike and India–Pakistan Aerial Escalation
February–March 2019What Happened
Following a suicide bombing in Pulwama that killed 40 Indian paramilitary personnel, India launched an airstrike on February 26, 2019, against what it described as a Jaish‑e‑Mohammed training camp near Balakot inside Pakistan. Pakistan denied major damage, vowed to respond, and the next day shot down an Indian jet and captured its pilot in a retaliatory operation. The crisis marked the first time since 1971 that warplanes from either side crossed the Line of Control and raised global fears about escalation between nuclear‑armed neighbours.
Outcome
Short term: Intense international pressure, including from the United States, led to the return of the captured Indian pilot and a rapid de‑escalation, though cross‑border fire persisted.
Long term: The episode demonstrated that limited cross‑border airstrikes can occur without full‑scale war but also highlighted how quickly miscalculation risks can rise when air power is used across disputed frontiers.
Why It's Relevant
Thailand’s December 2025 airstrikes into Cambodia are rare for Southeast Asia and invite comparison to Balakot: a limited cross‑border use of airpower in a territorial dispute. The India–Pakistan case suggests that strong external mediation can cap escalation, but also that such actions set precedents that may normalize interstate airstrikes in volatile regions.