EXPLAINER | Why are Thailand and Cambodia fighting?

Thailand and Cambodia are engaged in their worst fighting in more than a decade, exchanging heavy artillery fire across their disputed border, with at least 16 people killed and tens of thousands displaced.

People donate blood in Phnom Penh, Cambodia, on July 25 2025 after artillery volleys from Thailand and Cambodia killed civilians, as their worst fighting in more than a decade stretched for a second day.
People donate blood in Phnom Penh, Cambodia, on July 25 2025 after artillery volleys from Thailand and Cambodia killed civilians, as their worst fighting in more than a decade stretched for a second day. (REUTERS/Chantha Lach)

Thailand and Cambodia are engaged in their worst fighting in more than a decade, exchanging heavy artillery fire across their disputed border, with at least 16 people killed and tens of thousands displaced.

Tensions began rising between the Southeast Asian neighbours in May after the killing of a Cambodian soldier during a brief exchange of gunfire and have steadily escalated since, triggering diplomatic spats and armed clashes.

Clashes broke out between the two countries early on Thursday along a disputed area abutting an ancient temple, rapidly spilling over to other areas along the contested frontier and heavy artillery exchanges continuing for a second straight day.

Thailand recalled its ambassador to Phnom Penh on Wednesday and expelled Cambodia's envoy in response to a second Thai soldier losing a limb to a landmine that Bangkok alleged had been laid recently by rival troops. Cambodia called the accusation baseless.

The two sides accuse each other of firing the first shots that started the conflict on Thursday, which has so far claimed the lives of at least 15 civilians, most of them on the Thai side.

Cambodia has deployed truck-mounted rocket launchers, which Thailand said have been used to target civilian areas, while Thai armed forces dispatched US-made F-16 fighter jets, using one to bomb military targets across the border.

About 130,000 people have been evacuated from border areas in Thailand to safer locations and about 12,000 families on the Cambodian side have been shifted away from the front lines, according to local authorities.

Thailand and Cambodia have for more than a century contested sovereignty at undemarcated points along their 817km land border, which was first mapped by France in 1907 when Cambodia was its colony.

The map, which Thailand later contested, was based on an agreement that the border would be demarcated along the natural watershed line between the two countries.

In 2000, the two countries agreed to establish a joint boundary commission to peacefully address overlapping claims, but little progress has been made towards settling disputes. Claims over ownership of historical sites have raised nationalist tension between the two countries, notably in 2003 when rioters torched the Thai embassy and Thai businesses in Phnom Penh over an alleged remark by a Thai celebrity questioning jurisdiction over Cambodia's World Heritage-listed Angkor Wat temple.

An 11th century Hindu temple called Preah Vihear, or Khao Phra Viharn in Thailand, has been at the heart of the dispute for decades, with Bangkok and Phnom Penh claiming historical ownership.

The International Court of Justice (ICJ) awarded the temple to Cambodia in 1962, but Thailand has continued to lay claim to the surrounding land.

Tension escalated in 2008 after Cambodia attempted to list the Preah Vihear temple as a Unesco World Heritage site, leading to skirmishes over several years and at least a dozen deaths, including during a weeklong exchange of artillery in 2011. Two years later, Cambodia sought interpretation of the 1962 verdict and the ICJ again ruled in its favour, saying the land around the temple was also part of Cambodia and ordering Thai troops to withdraw.

Despite the historic rivalry, the governments of Thailand and Cambodia enjoy warm ties, partly due to the close relationship between their influential former leaders, Thailand's Thaksin Shinawatra and Cambodia's Hun Sen. However, nationalist sentiment has risen in Thailand after conservatives last year questioned the government's plan to negotiate with Cambodia to jointly explore energy resources in undemarcated maritime areas, warning such a move could risk Thailand losing the island of Koh Kood in the Gulf of Thailand.

Tensions also rose in February when a group of Cambodians escorted by troops sang their national anthem at another ancient Hindu temple which the two countries claim, Ta Moan Thom, before being stopped by Thai soldiers. An effort by then Thai premier Paetongtarn Shinawatra, Thaksin's daughter, to de-escalate the situation in a call last month with Hun Sen spectacularly backfired after a recording of the conversation was initially leaked and later released in full by the Cambodian leader.

During the call, the 38-year-old prime minister appeared to criticise a Thai army commander and kowtow to Hun Sen, drawing public fury and a complaint from a group of senators, which led to her suspension by a court order on July 1.

After the May 28 clash, the two countries quickly promised to ease tension, prevent more conflict and seek dialogue via their joint border commission at a June 14 meeting.

The neighbours have issued diplomatically worded statements committing to peace while vowing to protect sovereignty, but their militaries have been mobilising near the border. Cambodia said existing mechanisms were not working and it planned to refer disputes in four border areas to the ICJ to settle “unresolved and sensitive” issues it said could escalate tensions.

Thailand has not recognised the ICJ's rulings on the row and wants to settle it bilaterally. Since Thursday's clashes, Cambodia has written to the UN Security Council, urging the body to convene a meeting to stop what it describes as “unprovoked and premeditated military aggression” by Thailand.

Thailand wants to resolve the conflict through bilateral negotiations but said talks can only take place after Cambodia ceases violence.

Reuters 


Would you like to comment on this article?
Sign up (it's quick and free) or sign in now.

Comment icon