Cambodia is reported to have raised a national flag over Wat Kaew Sikha Khiri Sawara, after earlier destroying a controversial sign - sparking a new controversy over the disputed border area.
The flag was reported to have been raised after the contentious stone tablet with a message that the area belongs to Cambodia was demolished on Wednesday to great fanfare.
Prime Minister Abhisit Vejjajiva, when asked about this matter, said: "If this is true, the flag must be removed."
He said it was agreed by both sides not to put up any sign showing ownership in a disputed area.
However, Mr Abhisit said he did not know whether and where the Cambodian flag had really been raised.
Asked whether what happended during the past few weeks can be raised at a meeting of the World Heritage Committee, the prime minister said:
"Of course, we will have to report problems to the World Heritage Committee to let it know that if it wants to proceed with the management of an area in dispute, tension and serious conflict would follow. This would contravene the objectives of having a world heritage site."
Preah Vihear temple has been declared a world heritage site uindr Camboldian management by Unesco. Thailand has opposed the decision arguing that there will be problems managing it as long as the dispute over the land immediately adjoining it remains unsettled.