Thailand's military authorities reported a significant incident on Tuesday morning, January 6, 2026, when Cambodian forces allegedly fired mortar rounds across the border into Ubon Ratchathani province. The attack resulted in one Thai soldier sustaining shrapnel wounds, described as minor and non-life-threatening, who was promptly evacuated for medical treatment. This event marks a potential breach of the ceasefire agreement established on December 27, 2025, which had aimed to conclude three weeks of intense clashes that claimed numerous lives and displaced over a million people across both nations.

In response to the initial accusation of violation, Cambodian military representatives contacted Thai units, asserting that the cross-border fire was unintentional and stemmed from an operational error by their personnel, with no deliberate intent to target Thai territory. Despite this explanation, the Thai army issued a stern warning, urging Cambodian forces to exercise greater caution and stating that any recurrence could prompt retaliatory measures from Thailand.

Thai Prime Minister Anutin Charnvirakul announced that a formal protest had been lodged with Phnom Penh regarding the alleged truce violation. While acknowledging the Cambodian claim of an accident, he stressed the importance of receiving clear explanations on accountability. Emphasizing Thailand's superior military capabilities, the prime minister noted that provincial governors had been instructed to prepare contingency plans, although no civilian evacuations were mandated at that point. Hundreds of thousands of displaced individuals from the December fighting have since begun returning to their homes along the border.

Also Read: Thailand Accuses Cambodia of Ceasefire Breach After 250 Drones Cross Border

The enduring conflict between Thailand and Cambodia originates from disagreements over colonial-era border demarcations along their 800-kilometer frontier, involving contested territories and ancient temple ruins. Previous ceasefires throughout 2025, including one mediated by the United States, China, and Malaysia in July and a follow-on agreement in October, proved temporary, collapsing amid mutual accusations of provocations such as landmine deployments and airspace violations.

As of early January 2026, both sides continue to assert claims over disputed areas, with Cambodia recently proposing bilateral committee meetings in Siem Reap to address demarcation issues, while Thailand indicates such discussions may await outcomes from its upcoming February elections. The recent mortar incident underscores the persistent fragility of peace efforts, despite commitments under the December truce to cease hostilities, immobilize troop positions, and collaborate on demining operations along the contentious border.

Also Read: Thailand–Cambodia Agree to Immediate Ceasefire After Weeks of Deadly Border Clashes