The ministers of the Association of Southeast Asian Nations will seek to salvage a truce first brokered by ASEAN chair Malaysia and US President Donald Trump after a previous round of border clashes in July, their worst conflict in recent history.
Thailand and Cambodia's top diplomats attended the gathering in Kuala Lumpur, the first face-to-face meeting involving the two governments since the fighting resumed on December 8, as Malaysia urged the bloc to play a more forceful role in halting the conflict.
"It is my hope that this special meeting will renew our efforts for a return to stability in the affected areas. ASEAN must do whatever is necessary to maintain regional peace and stability," Malaysia's Foreign Minister Mohamad Hasan said in opening remarks to ministers.
"Our goal goes beyond de-escalating the tension. We must intensify trust-building among the conflicting parties and provide the horizons for dialogue despite the prevailing differences."
The regional peace push comes as the US and China pursue separate diplomatic efforts to end the conflict, with no signs of success so far.
Bangkok and Phnom Penh each accuse the other of aggression and moves that led to the breakdown of the truce and an enhanced ceasefire agreed in October in Malaysia in Trump's presence, during which they committed to demining and withdrawal of troops and heavy weapons.
Heavy exchanges of fire have occurred in multiple locations along their 817km land border, from forested inland areas near Laos to coastal provinces.
Cambodia's defence ministry said Thailand had violated its sovereignty with more "armed aggression" on Monday and vowed to defend what it said was its territory "at any cost".
Thailand on the weekend accused Cambodia of seeking to fire rockets on a border town and said a soldier had lost a leg to a landmine. Thailand has accused Cambodia of laying new mines in violation of its international treaty commitments, an allegation Phnom Penh has rejected.
Malaysian Prime Minister Anwar Ibrahim has expressed hope the meeting would enable Thailand and Cambodia to negotiate openly, resolve differences and achieve a fair and lasting solution.
"I emphasised the importance for Cambodia and Thailand to uphold the spirit of dialogue, wisdom and mutual respect in order to end the tensions and maintain peace and stability in this region," Anwar said on X, adding that he had spoken with both prime ministers.
Last week he said he was "cautiously optimistic" about the outcome of the meeting, adding that Thailand's caretaker premier Anutin Charnvirakul and Cambodian Prime Minister Hun Manet were both "keen to achieve an amicable resolution as soon as possible".
