Bangkok, July 29: Thailand has threatened to withdraw from the UN's World Heritage Committee if it approves a Cambodian management plan for an 11th-century Hindu temple straddling the two countries' border.
The Unesco World Heritage Committee was due to rule on the plan Thursday at a meeting in Brazil.
The temple, known in Cambodia as Phra Viharn and as Preah Vihear in Thailand, has been a bone of contention between Cambodia and Thailand for decades.
The International Court of Justice in 1962 ruled that the temple belonged to Cambodia, but failed to rule on adjacent land, leading to decades of tension and border troop skirmishes in late 2008.
Successive Thai governments have claimed the disputed area as belonging to the northeastern province of Si Sa Ket.
"If Unesco accepts the (Cambodian) plan, it will create a wide rift between the people of the two countries," the Bangkok Post newspaper quoted Prime Minister Abhisit Vejjajiva as saying at a cabinet meeting Wednesday.
Abhisit was quoted as saying his government would veto the plan and "consider withdrawing as a world heritage member".
Deputy Prime Minister Suthep Tuaksuban reiterated the government's position Thursday, accusing the UN committee of exacerbating tensions between Thailand and Cambodia.
"If the committee approves the Cambodian plan, we will not participate and will walk out," he told reporters at Government House. "The (World Heritage Committee) should avoid creating disputes between nations."
In addition to the dispute's diplomatic and possible military dimensions, it has become a thorny political problem for the Thai leader.
Ultra-nationalist leaders have seized on the border dispute, urging the government to take a tough line in rejecting Cambodia's management of the area around the temple.
Chamlong Srimuang, a leader of the People's Alliance for Democracy, and some 700 followers Tuesday protested against the Cambodian plan at the UNESCO office in Bangkok.
The protest, held in defiance of an emergency decree prohibiting political gatherings of more than five people, broke up peacefully after UN officials agreed to forward the group's demands to the world heritage meeting in Brasilia.
The emergency decree was aimed at followers of former prime minister Thaksin Shinawatra, who held a series of rallies in April and May that led to clashes and a military crackdown that killed 90 people.
Leaders of the anti-government, pro-Thaksin movement said the government's failure to suppress Tuesday's demonstration or prosecute its organisers were indications of its double standard in applying the emergency law.