More than 200,000 people have fled the frontier as the two exchanged artillery, rockets and gun fire in the long-disputed area, which is home to a collection of ancient temples.

A series of motorcades, including some sporting US and Chinese flags, arrived at Seri Perdana, Malaysian Prime Minister Anwar Ibrahim's official residence, on Monday afternoon.

A helicopter buzzed over the administrative capital as Thailand's acting Prime Minister Phumtham Wechayachai and Cambodia's Prime Minister Hun Manet met shortly after 0700 GMT.

Monday's meeting comes after US President Donald Trump intervened, making a late-night weekend call to both Southeast Asian leaders, who he said agreed to "quickly work out" a truce.

Anwar, whose country currently chairs the Association of Southeast Asian Nations (ASEAN), is mediating, while US State Department officials and a Chinese delegation were also present.

Ahead of the talks, Thailand and Cambodia traded fresh fire and accusations.

Phumtham said Bangkok did not believe Phnom Penh "is acting in good faith."

Meanwhile, Cambodia's defence ministry spokeswoman Maly Socheata said Monday was "the fifth day that Thailand has invaded Cambodia's territory with heavy weapons and with the deployment of a lot of troops".