At least four soldiers have been killed in fighting along the border between Thailand and Cambodia, raising the death toll to 10 in two days.
Troops exchanged artillery and gunfire in jungle around Ta Krabey temple, which both sides claim.
The area is about 200km (125 miles) west of the disputed 900-year-old Preah Vihear temple, the scene of deadly clashes in February.
Thousands of civilians have been evacuated from the area.
The BBC's Rachel Harvey in Bangkok says it is not immediately clear what sparked the most recent violence.
Both sides blamed each other for the fighting.
"Fresh fighting started at around 0600 (2300 GMT Friday) with rifles and mortar shelling," said Thai army spokesman Col Prawit Hookaew.
"We are negotiating to stop the fighting," he added.
Thai officials said one Thai soldier had been killed and more than four injured. Cambodian officials said three of their troops had died.
They said artillery shelling had also taken place, and described the fighting as more intense than that on Friday.
Cambodia said three of its soldiers were killed on Friday and six wounded while a Thai spokesman told the BBC that three of its soldiers had been killed and 11 injured.
Until Friday, an informal truce had appeared to be holding.
Indonesia, which has been negotiating peace talks between the two neighbours on behalf of the regional group Asean, has called for an immediate ceasefire.
Demarcation issue
Cambodia has made clear it wants international mediation, but Thailand insists the dispute can be resolved through existing bilateral channels.
However, events on the ground appear to be moving faster than the diplomatic process, our correspondent says.
Preah Vihear temple was awarded to Cambodia in 1962 by an international court.
But both sides claim ownership of the surrounding area, and there have been several skirmishes there in recent years.
Other parts of the Thai-Cambodian border have not yet been formally demarcated, causing continuing tensions between the two countries.
source : bbc.co.uk
