Cambodia and Thailand each said the other had launched artillery attacks across contested border areas early on Sunday, hours after US President Donald Trump said the leaders of both countries had agreed to work on a ceasefire.

Cambodia said it fully endorsed Trump’s call for an immediate ceasefire. Thailand said while it was grateful to the US President, it could not begin talks while Cambodia was targeting its civilians, a claim that Phnom Penh has denied.

"Our condition is that we do not want a third country but are thankful for his (Trump’s) concern," Thailand’s acting Prime Minister Phumtham Wechayachai told reporters before heading off to visit border areas.

"We’ve proposed a bilateral between our foreign ministers to conclude the conditions for a ceasefire and drawing back troops and long-range weapons."

Cambodia said Thailand had started hostilities on Sunday morning and that Thai forces were mobilising along the border. Thailand said it had responded to attacks from Cambodia.

"I made it clear to Honourable President Donald Trump that Cambodia agreed with the proposal for an immediate and unconditional ceasefire between the two armed forces," Cambodian Prime Minister Hun Manet posted on Facebook, noting he had also agreed to Malaysia’s earlier ceasefire proposal.

CITIZENS WANT PEACE

Four days after the worst fighting in more than a decade broke out between the Southeast Asian neighbours, the death toll stood above 30, including 13 civilians in Thailand and eight in Cambodia. More than 200,000 people have been evacuated from border areas in the two countries, authorities said.

Cambodia’s Defence Ministry said Thailand had shelled and launched ground assaults on Sunday morning at a number of points along the border. The ministry’s spokesperson said heavy artillery was fired at historic temple complexes.

"For me, I think it is great if Thailand agreed to stop fighting so both countries can live with peace," a Phnom Penh university student Sreung Nita told Reuters.

The Thai army said Cambodian forces had fired shots into several areas, including near civilian homes, early on Sunday, and were mobilising long-range rocket launchers. The governor of Surin told Reuters artillery shells had been fired into the province.

"The soldiers will continue to do their job at full steam - so Thais do not worry - until the government has reached a clear agreement that there is no danger for the people and to ensure we maintain the country’s interests in order to bring the peace we want to see," Phumtham said.

In the Thai province of Sisaket, Reuters reporters heard shelling throughout Sunday and said it was unclear which side of the border it was on.

"If there is a ceasefire, things will be better," Sisaket resident Thavorn Toosawan told Reuters. "It’s great that America is insisting on the ceasefire because it would bring peace."

TRUMP SPEAKS TO BOTH LEADERS

Trump said on Saturday that he had spoken with the prime ministers of Thailand and Cambodia and they had agreed to meet immediately to quickly work out a ceasefire to end fighting that began on Thursday. Bangkok and Phnom Penh each say the other started the hostilities last week.

"Both Parties are looking for an immediate Ceasefire and Peace," Trump wrote on social media, adding tariff negotiations with both countries were on hold until the fighting stopped.

The countries have faced off since the killing of a Cambodian soldier late in May during a brief skirmish. Troops on both sides of the border were reinforced amid a full-blown diplomatic crisis that brought Thailand’s fragile coalition government to the brink of collapse.

Thailand and Cambodia have bickered for decades over undemarcated points along their 817-km (508-mile) land border, with ownership of the ancient Hindu temples Ta Moan Thom and the 11th century Preah Vihear central to the disputes.

Preah Vihear was awarded to Cambodia by the International Court of Justice in 1962, but tension escalated in 2008 after Cambodia attempted to list it as a UNESCO World Heritage site, and skirmishes over several years brought at least a dozen deaths.

Cambodia said in June it had asked the world court to resolve its disputes with Thailand, which says it has never recognised the court’s jurisdiction and prefers a bilateral approach.