Bangkok/Phnom Penh, December 22, 2025 – Fresh fighting broke out along the Thailand-Cambodia border on Monday, just hours before Southeast Asian foreign ministers convened in Malaysia to discuss steps to de-escalate the deadly conflict between the neighboring nations.

The resurgence of violence threatens to undermine ongoing diplomatic efforts by the Association of Southeast Asian Nations (ASEAN), which is seeking to revive a ceasefire first brokered in July 2025 by Malaysia and U.S. President Donald Trump.

Recent Fighting and Civilian Impact

Since clashes resumed on December 8, at least 40 people have been killed, with nearly one million civilians displaced across both sides of the border.

The Cambodian Ministry of National Defence reported that Thai forces deployed F-16 fighter jets, dropping four bombs in Banteay Meanchey province, and allegedly fired toxic gas near Prey Chan village. The Cambodian army confirmed artillery shelling in Battambang province, wounding at least one civilian.

Video footage circulating online shows families, including children, taking shelter as explosions hit residential areas. Thai authorities have yet to comment on the renewed clashes.

On the Thai side, Prime Minister Anutin Charnvirakul claimed Thailand has not acted as the aggressor and stated that areas “previously encroached upon” by Cambodian forces have been reclaimed. Thai reports indicate around 400,000 people displaced in the affected provinces. Meanwhile, Cambodian authorities reported 525,000 civilians displaced and additional casualties in Oddar Meanchey province.

ASEAN Diplomatic Efforts

In Kuala Lumpur, representatives from Thailand and Cambodia attended their first face-to-face ASEAN meeting since hostilities resumed. The talks, chaired by Malaysian Foreign Minister Mohamad Hasan, focused on measures to de-escalate tensions, rebuild trust, and ensure a lasting ceasefire.

Hasan emphasized:

“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.”

Malaysian Prime Minister Anwar Ibrahim also expressed hope that the meeting would enable both sides to negotiate openly and achieve a fair and lasting resolution.

International Response

The U.S. Department of State called on Thailand and Cambodia to:

• End hostilities
• Withdraw heavy weapons
• Stop emplacement of landmines
• Fully implement the Kuala Lumpur Peace Accords

The U.S. welcomed ASEAN’s role in supporting both countries to honor their commitments. Additionally, China and the U.S. have separately pursued diplomatic efforts, though no tangible outcomes have emerged.

Both Bangkok and Phnom Penh continue to trade blame for violations of previous ceasefires, including the July accord and an extended agreement signed in October 2025.

Background

The Thailand-Cambodia border conflict has flared intermittently for decades over territorial disputes, with both nations accusing the other of encroachments and ceasefire violations. The current clashes have intensified regional concerns, given the humanitarian toll and the proximity to ASEAN-led diplomatic negotiations.