Donald Trump has said he believed both Thailand and Cambodia wanted to settle their differences after he told the leaders of both countries that he would not conclude trade deals with them unless they ended their fighting.

On Monday, Thai and Cambodian leaders will meet in Malaysia for talks to end hostilities, a spokesperson for the Thai prime minister’s office said on Sunday. The deadly border dispute, now in its fourth day, has killed at least 35 people and displaced more than 218,000.

Trump told reporters in Turnbery, Scotland: “I spoke to both of the prime ministers, and I think by the time I got off, I think they want to settle now.”

A spokesperson for Thailand’s acting prime minister, Phumtham Wechayachai, said the leader would attend Monday’s talks in response to an invitation from Malaysian prime minister Anwar Ibrahim “to discuss peace efforts in the region”. Anwar has been acting in his capacity as this year’s chair of the 10-member Association of Southeast Asian Nations (Asean).

Cambodian prime minister Hun Manet confirmed his participation as well. “I will lead [the] Cambodian delegation to attend a special meeting in Kuala Lumpur hosted by Malaysia, co-organised by the United States and with participation of China,” he said.

China is a close ally of Cambodia, and early in the fighting urged the two nations to resolve their differences peacefully. Hun Manet’s statement appeared to be the first mention of a Chinese link to Monday’s planned talks.

Trump posted on the Truth Social social network on Saturday that he spoke to the leaders of Thailand and Cambodia and suggested he would not move forward with trade agreements with either country if the hostilities continued.

Hun Manet said earlier on Sunday his country agreed to pursue an “immediate and unconditional ceasefire”. He said Trump told him that Thailand had also agreed to halt attacks after the US president’s conversation with Phumtham.

Phumtham thanked Trump and qualified Thailand’s position, saying it agreed in principle to a ceasefire but stressed the need for “sincere intention” from Cambodia, the Thai foreign ministry said.

US state department spokesperson Tammy Bruce on Sunday said the US “is prepared to facilitate future discussions in order to ensure peace and stability” between the two countries, and that secretary of state Marco Rubio had spoken to the foreign ministers of both Thailand and Cambodia, urging them “to de-escalate tensions immediately and agree to a ceasefire”.

The fighting flared on Thursday after a landmine explosion along the border wounded five Thai soldiers. Both sides blamed each other for starting the clashes. Both countries recalled their ambassadors and Thailand closed its border crossings with Cambodia, with an exception for migrant Cambodian workers returning home.

Despite the diplomatic efforts, fighting continued on Sunday along parts of the contested border, with both sides refusing to budge and trading blame over renewed shelling and troop movements.

Colonel Richa Suksowanont, a Thai army deputy spokesperson, said Cambodian forces fired heavy artillery into Surin province, including at civilian homes, early on Sunday. He said Cambodia also launched rocket attacks targeting the ancient Ta Muen Thom temple, claimed by both countries, and other areas in a bid to reclaim territory secured by Thai troops. Thai forces responded with long-range artillery to strike Cambodian artillery and rocket launchers.

Battlefield operations would continue and a ceasefire can only happen if Cambodia formally initiates negotiations, he added.

“Cambodian attacks remain irregular and may constitute violations of rules of engagement, posing further risk to border communities,” said the Thai military’s daily summary of the fighting issued on Sunday night.

“The situation remains highly tense, and it is anticipated that Cambodia may be preparing for a major military operation prior to entering negotiations,” it said.

Cambodian defense ministry spokesperson Lt Gen Maly Socheata accused Thai forces of escalating the violence with bombardment of Cambodian territory early on Sunday, followed by a “large-scale incursion” involving tanks and ground troops in multiple areas.

“Such actions undermine all efforts toward peaceful resolution and expose Thailand’s clear intent to escalate rather than de-escalate the conflict,” she said.

Thailand on Sunday reported a new death of a soldier, bringing its total number of fatalities to 22, mostly civilians. Cambodia said 13 people have been killed, though it was unclear if that included Lt. Gen. Duong Samnieng, whose death in combat was announced on Sunday.

More than 139,000 people in Thailand have evacuated to safe locations and over 79,000 people fled from three Cambodian provinces. Many border villages are mostly deserted, with many schools and hospitals shut.

With Associated Press and Reuters