US President Donald Trump said Friday that Thailand and Cambodia had agreed to halt fighting along their disputed border, which has killed at least 20 people this week.

The latest fighting between the Southeast Asian neighbours, which stems from a long-running dispute over the colonial-era demarcation of their 800-kilometre (500-mile) frontier, has also displaced around half a million on both sides.

Each side had blamed the other for reigniting the conflict.

"I had a very good conversation this morning with the Prime Minister of Thailand, Anutin Charnvirakul, and the Prime Minister of Cambodia, Hun Manet, concerning the very unfortunate reawakening of their long-running War," Trump said on his Truth Social platform.

"They have agreed to CEASE all shooting effective this evening, and go back to the original Peace Accord made with me, and them, with the help of the Great Prime Minister of Malaysia, Anwar Ibrahim," he said, referring to a deal made in July.

"Both Countries are ready for PEACE and continued Trade with the United States of America," Trump noted, thanking Anwar for his assistance.

Earlier, Anutin had said, after his call with Trump:"It needs to be announced to the world that Cambodia is going to comply with the ceasefire."

"The one who violated the agreement needs to fix (the situation) – not the one that got violated," Anutin said, adding that the call with Trump"went well".

'Talk among themselves'

The United States, China and Malaysia, as chair of the regional bloc ASEAN, brokered a ceasefire in July after an initial five-day spate of violence.

In October, Trump backed a follow-on joint declaration between Thailand and Cambodia, touting new trade deals after they agreed to prolong their truce.

But Thailand suspended the agreement the following month after Thai soldiers were wounded by landmines at the border.

In the northeastern province of Buriram, Thai evacuee Jirasan Kongchan said peace should come through direct bilateral talks, not foreign mediation.

"I want Thailand and Cambodia to talk among themselves first, clearly and decisively," said the 50-year-old farmer."If Cambodia breaks the peace (agreement) again, ASEAN countries should step in, maybe impose some kind of sanctions."

Cambodian evacuee Choeun Samnang, 54, said he was"very happy" to hear Trump had called the Thai prime minister asking for the countries to abide by the joint declaration.

"I don't want to see countries at war. I want both Cambodia and Thailand to have peace," he said at a shelter in Banteay Meanchey province.

At the White House on Thursday, Trump again boasted about having resolved multiple conflicts, but said that with"Thailand and Cambodia, I think I'm going to have to make a couple of phone calls... but we'll get that one back on track".

Anutin said there were"no signs" Trump would connect further trade talks with the border conflict, but that he had guaranteed Thailand would get"better benefits than other countries".