More than 500,000 people have fled their homes to safety in Thailand and Cambodia since the start of a reignited border conflict, both governments said on Wednesday, surpassing the total number evacuated during similar clashes earlier this year.

"Civilians have had to evacuate in large numbers due to what we assessed as an imminent threat to their safety. More than 400,000 people have been moved to safe shelters" across seven provinces, Thai defence ministry spokesperson Surasant Kongsiri told reporters at a news conference.

"We want to prevent a recurrence of the attacks on civilians we suffered in July 2025."

In Cambodia, "101,229 people have been evacuated to safe shelters and relatives' homes in five provinces," as of Tuesday evening, defence ministry spokeswoman Maly Socheata told reporters.

The Southeast Asian neighbours dispute the colonial-era demarcation of their 800-kilometre frontier, where competing claims to historic temples have spilled over into armed conflict.

The renewed fighting has resulted in Cambodia withdrawing from the South East Asian Games, being hosted by Thailand, in protest.

Thailand's foreign minister said in an interview on Tuesday that he saw no potential for negotiations in the border conflict, adding the situation was not conducive to third-party mediation, while a top adviser to Cambodia's Prime Minister Hun Manet told foreign media his country was "ready to talk at any time".

US President Donald Trump said he would make a phone call to stop the conflict, after he had brokered a ceasefire in July to end a five-day battle between the Asian neighbours.

Speaking at a rally in Pennsylvania on Tuesday, Trump listed a number of wars that he claimed he helped stop, including between Pakistan and India, and Israel and Iran, before stopping on the renewed conflict in Southeast Asia.

"I am going to have to make a phone call. Who else could say I'm going to make a phone call and stop a war of two very powerful countries, Thailand and Cambodia."

This week's clashes are the deadliest since five days of fighting in July that killed dozens and displaced around 300,000 on both sides of the border before a shaky truce was agreed, following an intervention by Trump. (Agencies)