Cambodian and Thai troops have exchanged fire in a disputed border area for a fourth consecutive day. At least five people were killed in clashes over the weekend and thousands of civilians have fled the area.
UN Secretary General Ban Ki-moon has called on both sides to "exercise maximum restraint".
This is the worst fighting between the two neighbours in years. The clashes have claimed the lives of two soldiers and a civilian from Cambodia, one Thai soldier and a Thai civilian.
However the two countries' media has reported differing casualty figures.
The Cambodian government says a Thai bombardment has damaged a wing of the ancient temple - a claim the Thais have not reacted to.
On Sunday, Cambodian Prime Minister Hun Sen asked the UN Security Council to intervene to stop what he said was Thailand's "repeated acts of aggression" against his country.
The regional grouping Asean has offered to mediate while Mr Ban has said the UN "remains at their disposal to assist in these peaceful efforts", but Thailand has said there is no need forthird-party involvement.
'Clear policy'
After a relatively quiet night on Sunday, fire was again exchanged both ways across the border at about 0800 local time (0100GMT) on Monday.
The BBC's Rachel Harvey in Bangkok says that all talk of ceasefires and negotiation now appear to have been abandoned. Thousands of people are reported to have fled their homes on both sides of the border after the fighting broke out on Friday.
Each country accuses the other of encroaching on its territory and of firing first.
Cambodia says the Thais started shooting four days ago, but a unnamed Thai military source said it had been "a misunderstanding".
Thai government spokesman Panitan Wattanayagorn later told reporters his country "has clear policy that we will not invade any country".
Thai Prime Minister Abhisit Vejjajiva has called for a peaceful solution, but warned that Thai soldiers would always defend Thai sovereignty if attacked.
An international court ruled in 1962 said that the Preah Vihear temple belonged to Cambodia, but the surrounding area is claimed by both sides.
In 2008, Cambodia was awarded Unesco World Heritage status for the temple, which further angered Thailand.
The most recent tension was sparked last week, when a Cambodian court sentenced two members of a Thai nationalist movement to up to eight years in prison after finding them guilty of espionage.
The two were among seven Thai politicians and activists charged with illegal entry by Cambodia after crossing into a disputed border area in December.
The case has outraged Thai nationalists.
Members of the People's Alliance for Democracy (PAD), known as the "yellow-shirts", have been staging protests in Bangkok, urging the government to take a tougher line over the border issue.
