Thailand has withdrawn from UNESCO's World Heritage convention because of a simmering dispute with Cambodia over a 900-year-old temple in a remote border area between the two countries.

Several military clashes at and near Preah Vihear temple since early February have left more than 20 people dead and displaced thousands of others.

Thailand says its withdrawal stems from what it calls a disappointing decision by the World Heritage governing body to place Cambodia's management plan for the temple on its agenda. Bangkok insists contested border demarcation issues be settled before any management plan is considered.

Thailand also insists those issues be settled in direct talks with Phnom Penh, and has balked at outside efforts to ease tensions by the United Nations and the regional grouping, the Association of Southeast Asian Nations (ASEAN).

Cambodia, in May, launched a legal bid at the International Court of Justice — the highest U.N. tribunal — seeking to force Thailand to withdraw its troops from disputed land near the temple. No ruling has been issued.

The temple, called Preah Vihear in Cambodia and Phra Viharn in Thailand, was declared a World heritage site in 2008. Both sides agree the temple lies in Cambodian territory. The dispute centers on access to the temple, which can only be gained by crossing through Thai territory.