BANGKOK, July 16 (Xinhua) -- About 250 Thai troops have been deployed near the Cambodian border since Tuesday following Cambodia's arrest of three Thai citizens who crossed into the disputed border area where the controversial Temple of Preah Vihear stands, Thai state-run Thai News Agency Wednesday reported.

　　The trio were returned to Thailand later on Tuesday, but Thais are being warned not to travel to the vicinity of Preah Vihear.

　　Meanwhile, military sources were quoted as saying that Cambodian troops have been reinforced nearby the area of overlapping claims.

　　The troop movements by both countries heightened tension at the border, and the Thai authorities have restricted vehicles and media from a 10 kilometers radius of the ancient temple, the report said.

　　Lt-Gen. Suchit Sitthiprapha, Thailand's Second Army Region commander, was quoted as saying that the protesters were being interviewed by the Suranaree Task Force and are "not being detained".

　　The trio, including a Buddhist monk, were detained briefly by Cambodian authorities on Tuesday after they had sneaked into the disputed area adjacent to the 11th century temple.

　　It was the first cross-border protest since Cambodia blocked access to Preah Vihear temple to visitors from Thailand last month, after some Thai protesters attempted to march on the temple ruins.

　　Suchit said the area adjacent to the temple was still disputed between the two countries, which means that there are differing ideas as to where the border is.

　　Meanwhile, some local and foreign reports said more than a dozen cross-border Thai military men have been detained by the Cambodia authorities on Tuesday. But it could not be confirmed by the Thai military.

　　The Preah Vihear site was awarded a World Heritage Site status by the United Nations Educational, Scientific and Cultural Organization (UNESCO) on July 7.