Thailand has launched air strikes along its disputed border with Cambodia, the Thai military said on Monday, after both countries accused the other of breaching a ceasefire agreement brokered by US President Donald Trump.

At least one Thai soldier has been killed and four wounded in the fresh clashes that broke out around two areas in the easternmost province of Ubon Ratchathani, Thailand’s military said in a statement, after its troops came under Cambodian fire.

“The Thai side has now begun using aircraft to strike military targets in several areas,” the statement said.

Cambodia’s defence ministry said in a statement that the Thai military had launched dawn attacks on its forces at two locations, following days of provocative actions, and added that Cambodian troops had not retaliated.

Thailand’s army said Cambodia’s military had fired BM-21 rockets towards Thai civilian areas, adding there were no reports of casualties.

Meanwhile, Malaysian Prime Minister Anwar Ibrahim urged Thailand and Cambodia to exercise restraint, warning the fighting risked undoing the careful work that went into a ceasefire he helped to broker.

“We urge both sides to exercise maximum restraint, maintain open channels of communication and make full use of the mechanisms in place,” Anwar, the chair of the regional bloc ASEAN, said in a post on X.

Ceasefire breakdown

The border dispute had erupted into a five-day conflict in July, before a ceasefire deal brokered by Malaysian Prime Minister Anwar Ibrahim and Trump, who also witnessed the signing of an expanded peace agreement between the two countries in Kuala Lumpur in October.

At least 48 people were killed and an estimated 300,000 temporarily displaced during the July clashes, with the neighbours exchanging rockets and heavy artillery fire.

Following a landmine blast last month that maimed one of its soldiers, Thailand said it was halting the implementation of the ceasefire pact with Cambodia.

Cambodia’s influential former longtime leader Hun Sen, father of current premier Hun Manet, said Thailand’s military were “aggressors” seeking to provoke a retaliatory response and urged Cambodian forces to exercise restraint.

“The red line for responding has already been set. I urge commanders at all levels to educate all officers and soldiers accordingly,” Hun Sen said on Facebook, without elaborating.

In Thailand, more than 385,000 civilians across four border districts are being evacuated, with over 35,000 already housed in temporary shelters, the Thai military said.

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

Simmering tension has occasionally exploded into skirmishes, such as a weeklong artillery exchange in 2011, despite attempts to peacefully resolve overlapping claims.