In the past few weeks, both countries have moved troops into the area near the temple, which lies in disputed land.
Thailand's Tej Bunnag and Cambodia's Hor Namhong are attempting to end a border row that began a century ago. Although the International Court of Justice ruled in 1962 that the temple itself belonged to Cambodia, the surrounding land remained disputed.
In January 1978, Vietnamese government troops invaded Cambodia to overthrow the Khmer Rouge, and according to reports, launched attacks on forces loyal to Pol Pot who had taken shelter in the temple. There were no reports of damage to the building.
Tensions broke out earlier this month when Cambodia successfully applied to have Preah Vihear placed on the world heritage list.
Thailand's Constitutional Court rejected the move.
There have been minor altercations between Thai protesters and Cambodian soldiers since then.
