The border clashes between Thailand and Cambodia have claimed the lives of 53 civilians from both countries as of December 21, according to China News Service. Cambodia’s Ministry of Interior reported that at least 19 Cambodian civilians were killed and 79 injured, with more than 510,000 people displaced from their homes.

A Thai Defense Ministry spokesperson said that 34 Thai civilians have lost their lives in the conflict. In addition, data released by Thailand's Joint Press Center for Thai-Cambodian Border Affairs on December 18 showed that 21 Thai soldiers were killed.

On-ground situation remains tense

The conflict continues to escalate as of December 21, Xinhua News Agency reported. On the afternoon of December 21, Cambodian forces continued shelling border areas in Thailand's Sa Kaeo Province. Thai troops have taken initial control of the strategically significant Highland 350 in the disputed border region.

Thailand also deployed F-16 fighter jets to destroy a Cambodian weapons depot hidden in an abandoned casino and launched airstrikes on Cambodian weapons supply lines, while Cambodian forces counterattacked with drones and rocket launchers.

Both sides have issued statements regarding the conflict. 

At a press conference on December 21, Cambodian Defense Ministry spokesperson Meas Sopheakdet reported the civilian casualties on the Cambodian side, noting that Thai military attacks pose a major security threat to innocent Cambodian civilians and world cultural heritage sites. 

Thai Prime Minister Anutin Charnvirakul stated on the same day that Thailand's armed forces have taken control of nearly all target areas, forcing Cambodian troops to withdraw. He added that Thai authorities have implemented strict surveillance in these areas to prevent further escalation of the conflict.

China, ASEAN step up diplomatic mediation

China and the Association of Southeast Asian Nations (ASEAN) have been actively mediating to de-escalate the situation. 

According to China's Foreign Ministry, China has continued its constructive shuttle diplomacy to cool tensions. On December 18, Wang Yi, member of the Political Bureau of the Communist Party of China Central Committee and Minister of Foreign Affairs, held separate phone calls with Prak Sokhonn, Cambodian Deputy Prime Minister and Minister of Foreign Affairs and International Cooperation, and Thai Foreign Minister Sihasak Phuangketkeow.

Both Cambodia and Thailand expressed their willingness to de-escalate tensions and achieve a ceasefire during the calls. Deng Xijun, China's Special Envoy for Asian Affairs, departed for Cambodia and Thailand on December 18 to conduct shuttle mediation. Cambodia highly commended and thanked China for its positive efforts in promoting the de-escalation of the Thai-Cambodian situation.

On the ASEAN front, an Extraordinary Meeting of ASEAN Foreign Ministers will be held in Kuala Lumpur, Malaysia, on December 22. 

Both Cambodia and Thailand have confirmed their attendance. 

Malaysian Prime Minister Anwar Ibrahim expressed hope that the meeting would help ease tensions between the two countries. The meeting, hosted by Malaysia in its capacity as ASEAN Chair, aims to advance dialogue and implement previous consensus on de-escalation.

The border dispute between Thailand and Cambodia has historical roots in unresolved territorial claims dating back to the colonial era, with the Preah Vihear Temple area long being a focal point of contention. 

The latest round of clashes erupted on December 7, following months of intermittent tensions and a peace declaration signed in October that failed to address core disputes.