Thailand’s decision to launch airstrikes on Cambodian territory has plunged a fragile Trump-brokered peace agreement into crisis, reigniting one of Southeast Asia’s most volatile border disputes and forcing mass civilian evacuations on both sides of the frontier. The Royal Thai Air Force struck Cambodian positions along the disputed frontier early Monday, in what Bangkok described as a defensive response to Cambodian artillery and rocket fire that killed a Thai soldier and wounded several others.

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Border clashes shatter a six-week-old truce

The air campaign, launched in the pre-dawn hours of December 8, 2025, marks the most serious escalation since a five‑day conflict in July that left at least 48 people dead and displaced around 300,000 civilians amid heavy artillery exchanges and earlier Thai air operations. Independent tallies from Thai and Cambodian authorities during the July flare‑up cited comparable casualty figures and large-scale displacements in border provinces such as Ubon Ratchathani, Preah Vihear and Oddar Meanchey. Monday’s strikes come barely six weeks after Thailand and Cambodia signed a ceasefire and political framework agreement in October under pressure from U.S. President Donald Trump, who had touted the deal as proof of his ability to resolve long‑running international conflicts. The renewed violence now threatens to unravel that accord, which required both sides to pull back heavy weapons, establish demilitarized buffer zones and participate in joint border monitoring.

Competing narratives over who fired first

Bangkok and Phnom Penh present starkly different accounts of how the latest round of fighting began—an ambiguity that has long characterized their border confrontations.

Thai officials say Cambodian forces opened fire around 3 a.m. local time, using artillery and mortars against Thai positions at Anupong Base, killing one Thai soldier and injuring at least seven others. In response, the Thai army requested air support “to suppress supporting fire” from Cambodian batteries near the Chong An Ma Pass and other contested sectors, according to army spokesman Maj. Gen. Winthai Suvaree. The Royal Thai Air Force later confirmed that fighter jets had targeted Cambodian military infrastructure, including weapons depots and suspected artillery positions assessed as direct threats to Thai territory.

Cambodia flatly rejects that version of events. Its Ministry of National Defense accuses Thailand of launching an attack at around 5:04 a.m. against Cambodian positions in Preah Vihear province after days of Thai “provocations,” and insists Cambodian troops did not return fire or deploy heavy weapons during the initial barrage. Phnom Penh says Thai forces shelled border villages, burned homes and forced residents to flee in northern provinces including Oddar Meanchey and Preah Vihear, framing the operation as an act of aggression that violates the October agreement and international law.

Civilian toll mounts as evacuations widen

Beyond the competing battlefield narratives, it is civilians who are once again bearing the brunt of the crisis.

Cambodian officials say at least four civilians have been killed and nine injured in the latest fighting, citing shelling and airstrikes near border communities in Preah Vihear province. Thailand, meanwhile, reports one soldier killed and at least eight wounded, and has ordered the evacuation of more than 385,000 people from a swath of districts along its northeastern border, with over 35,000 already relocated to temporary shelters in provinces such as Buriram and Ubon Ratchathani, according to military briefings. On the Cambodian side, authorities say more than 1,100 families have been moved away from frontline areas and several schools along the frontier have closed, disrupting education for thousands of students as classes are abruptly suspended and children rushed home amid nearby explosions.

Trump’s peace agreement under intense scrutiny

The renewed clashes are a sharp rebuke to former President Trump’s October peace initiative, which was framed in Washington as a signature diplomatic success in an election year.

Under the agreement, hammered out in talks involving Trump, Malaysian Prime Minister Anwar Ibrahim and the leaders of Thailand and Cambodia, both sides pledged to cease hostilities, pull back heavy weaponry and engage in further political dialogue backed by the prospect of economic incentives and the threat of sanctions. Trump boasted that the truce was one of several international conflicts he had “ended” in 2025, but the rapid resumption of hostilities has raised questions about the durability of high‑profile, leader‑driven deals that lack deep institutional buy‑in or robust monitoring mechanisms. Thai officials had already signaled mounting frustration last month, announcing that progress on the accord would be frozen after a Thai soldier was badly wounded by what Bangkok alleged was a newly laid Cambodian landmine along the border, a claim Cambodia denied.

Strategic weapons and fears of wider escalation

Thai military planners say the latest airstrikes were driven in part by intelligence that Cambodia had moved long‑range rocket systems close to the frontier, heightening concerns that key civilian infrastructure could fall within range.

According to Thai defense officials, Cambodian units in border provinces were believed to be operating Chinese‑made PHL‑03 multiple rocket launchers—with an estimated range of 70 to 130 kilometers—alongside older Soviet‑designed BM‑21 Grad systems with a shorter 15‑ to 40‑kilometer reach. That arsenal, they argue, placed potential targets such as the Buriram provincial airport and regional hospitals within theoretical strike distance, justifying pre‑emptive action to “degrade” Cambodian capabilities before any attack on civilian sites could be launched. Cambodia dismisses those claims as exaggerated and insists it has not targeted Thai civilians, instead accusing Bangkok of using the rocket allegations as a pretext for a disproportionate show of force.

A century-old border dispute

The latest crisis is rooted in a complex, century‑old dispute over the roughly 500‑mile (800‑kilometer) land border between Thailand and Cambodia, much of it drawn during the French colonial era when Cambodia was part of French Indochina. Thailand has long rejected portions of a French‑era map that placed culturally and strategically significant sites—most notably the Preah Vihear temple and surrounding high ground—on the Cambodian side of the line, even after an International Court of Justice ruling in 1962 confirmed Cambodian sovereignty over the temple complex. Periodic flare‑ups in 2008, 2011 and again in 2025 have turned this cartographic ambiguity into live-fire confrontations, underscoring how historical grievances can repeatedly derail attempts at peaceful resolution.

Regional and international calls for restraint

The renewed fighting has prompted urgent appeals from regional and international actors, anxious that a localized border conflict could destabilize wider Southeast Asia.

Malaysia, which currently chairs the Association of Southeast Asian Nations (ASEAN), has urged both parties to respect their October commitments and return to dialogue, warning that continued hostilities risk undermining confidence in ASEAN’s ability to manage regional security crises. The United Nations has also called for an immediate cessation of violence and emphasized the need to protect civilians and essential infrastructure, while U.S. officials say Trump “expects” both governments to honor the peace framework they signed. But Thailand’s Prime Minister Anutin Charnvirakul has so far taken a hard line, insisting Bangkok “never wished for violence” but will “never tolerate a violation of its sovereignty,” and leaving open the possibility of further military action if Thailand believes its territorial integrity is at risk.

Uncertain path back to peace

As Thai jets continue to patrol the skies near the border and artillery positions on both sides remain on high alert, prospects for an immediate return to the Trump-brokered peace plan appear dim.

To restore even a fragile calm, diplomats and regional mediators will need to bridge not only diverging accounts of who violated the ceasefire, but also deeper mistrust tied to history, domestic politics and shifting regional power dynamics. That could entail strengthening independent monitoring along the border, clarifying demarcation lines in especially contested sectors, and insulating any future agreement from rapid collapse when the next incident—whether a landmine explosion, a misfired shell or a disputed patrol—inevitably occurs. For now, the renewed fighting has turned one of Trump’s most publicized diplomatic achievements into an open question—and left tens of thousands of ordinary Thais and Cambodians once again fleeing a frontier that, for all the maps and treaties drawn over it, remains bitterly contested and acutely dangerous.