Military action against Cambodia will continue until Thailand’s sovereignty and territorial integrity are secured, Thailand’s foreign ministry said on Monday.

Foreign ministry spokesman Nikorndej Balankura said Cambodia had “trampled” on a ceasefire agreement between the two countries.

Fighting broke out in multiple areas along their disputed border, after both countries accused the other of breaching a ceasefire brokered by US President Donald Trump.

At least one Thai soldier had been killed and eight were wounded in the fresh clashes that intensified around 5am local time (10pm GMT on Sunday), a Thai army spokesman said, adding that air support was called in to hit Cambodian military targets.

Thailand’s Air Force said that Cambodia mobilised heavy weaponry, repositioned combat units and prepared support elements that could escalate military operations.

“These developments prompted the use of air power to deter and reduce Cambodia’s military capabilities,” it said in a statement.

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 responded.

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

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

Three Cambodian civilians have been seriously injured in the fighting so far, according to a senior provincial official. Cambodia’s defence ministry said its forces had not retaliated.

A simmering border dispute between the countries 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.

Anwar, chair of the Association of Southeast Asian Nations bloc, urged both sides to exercise maximum restraint and maintain open channels of communication.

“The renewed fighting risks unravelling the careful work that has gone into stabilising relations between the two neighbours,” Anwar said in a post on X.

Southeast Asian countries have rarely engaged in military clashes among themselves in recent decades, with the use of cross-border air strikes even rarer.

Phichet Pholkoet, a resident of Thailand’s Ban Kruat district which adjoins Cambodia, said he has heard gunfire since early Monday morning.

“It startled me. The explosions were very clear. Boom boom!” he said via telephone. “I could hear everything clearly. Some are heavy artillery, some are small arms.”

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

Across the border in Cambodia, opposition politician Meach Sovannara said civilians were also moving away from the fighting along the frontier.

“I heard the artillery shelling,” he told Reuters in an audio message from Samroang town, the capital of Oddar Meanchey Province, which abuts Thailand.

More than 1,100 families in Oddar Meanchey had been evacuated, authorities there said.

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 for five days.

Thailand and Cambodia have for more than a century contested sovereignty at non-demarcated points along their 817-km (508-mile) land border, first mapped in 1907 by France when it ruled Cambodia as a colony.

The long-standing dispute has occasionally exploded into skirmishes, such as a weeklong artillery exchange in 2011, despite attempts to peacefully resolve overlapping claims.

Tensions began rising in May this year, following the killing of a Cambodian soldier during a brief exchange of gunfire, and steadily escalated into diplomatic spats and armed clashes.

Although Anwar and Trump were able to halt the fighting within days and then cemented a ceasefire agreement at a regional summit in October. Thailand said it was halting the implementation of the truce with Cambodia last month, following a landmine blast that maimed one of its soldiers.

Thailand has repeatedly accused Cambodia of planting fresh landmines along parts of their disputed border, which have seriously injured at least seven Thai soldiers since July.

Phnom Penh denies the charge.

Some of the mines found along the frontier were likely newly laid, Reuters reported in October, based on expert analysis of material shared by Thailand’s military.g 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.

Timeline of conflict

MAY 28, 2025: Cambodia’s defence ministry says one of its soldiers is killed after a brief exchange of gunfire with Thai soldiers at a disputed border area, the first such deadly clash since 2011.

JULY 23: Thailand recalls its ambassador to Cambodia and says it will expel Cambodia’s ambassador, following a landmine incident that injured a Thai soldier along the disputed border.

JULY 24: Armed clashes erupt along the border. Both sides accuse the other of opening fire first. Thailand deploys F-16 jets, one of which bombs a Cambodian military target.

JULY 25: Fighting intensifies and spreads with heavy artillery fire and rocket attacks across multiple frontlines, marking their worst clashes in more than a decade. Fighting in the days that follow kills at least 48 people – mostly civilians – and an estimated 300,000 residents are displaced.

JULY 26: U.S. President Donald Trump calls leaders of both countries and says both agreed to meet soon to work out a ceasefire, adding their respective talks with Washington on trade tariffs could resume once a truce is in place.

JULY 28: After efforts by Malaysia, the United States and also China to bring both sides to the table, the two countries’ leaders sign an agreement in Malaysia’s Putrajaya to end hostilities, resume direct communications and create a mechanism to implement the ceasefire.

OCTOBER 26: The leaders of Thailand and Cambodia sign an enhanced ceasefire deal in the presence of Trump, whose intervention in their fierce border conflict earned him a Nobel Peace Prize nomination from Cambodia. The agreement builds on the truce signed three months earlier.

NOVEMBER 1: As part of the agreement, both countries say they have begun the phased withdrawal of heavy weapons from the disputed border, starting with rocket systems, and conducting de-mining operations. Cambodia says it expects the withdrawal to be fully completed by end of the year.

NOVEMBER 11: Thailand says it is halting implementation of the ceasefire pact with Cambodia a day after a landmine blast maimed a Thai soldier. Cambodia’s defence ministry denies having laid new landmines.

NOVEMBER 12: At least one person is killed in Cambodia as the neighbours accused each other of opening fire.

DECEMBER 8: Thailand launches air strikes after it said its troops came under Cambodian fire. Both countries accuse the other of breaching the ceasefire agreement and Thai authorities say hundreds of thousands of civilians are being evacuated.

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 817-km (508-mile) 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.