Southeast Asian neighbours of Thailand and Cambodia have urged the two countries to tone down hostile rhetoric over a disputed strip of land and an ancient temple, before violence breaks out.

The Association of South East Asian Nations (ASEAN) offered to mediate in the dispute Tuesday, said Singapore's Foreign Minister George Yeo, but no consensus could be reached on how best the organization could be involved.

Thailand and Cambodia are members of ASEAN and both must give their consent to any mediation.

Cambodia appealed late Monday to the United Nations Security Council to help resolve the standoff, which already involves heavily armed soldiers on both sides of the disputed area, about 250 kilometres north of Phnom Penh.

'In the face of this imminent state of war...we have an obligation to resort to the UN Security council.'—Cambodia's Foreign Minister

"In the face of this imminent state of war, this very serious threat to our independence and territorial integrity, we have an obligation to resort to the UN Security Council," said a statement from Cambodia's foreign minister Hor Namhong.

Thai Foreign Ministry spokesman Tharit Charrungvat said every state had the right to appeal to the UN, adding "we believe bilateral options are still not exhausted [in the dispute]."

Both countries lay claim to the Preah Vihear temple complex, an ancient Hindu site built by the same Khmer dynasty as the internationally renowned Angkor Wat temples in central Cambodia.

Dispute dates to colonial days

Thai forces occupied land around the temple in 1954 when France withdrew its soldiers from newly independent Cambodia.

International legal authorities have found in favour of Cambodia’s claim in the past, but Thailand has rejected such rulings.

The dispute simmered for decades but flared dangerously earlier this month when UNESCO accepted Cambodia's request to declare the temple complex a world heritage site, a move seen in Phomn Penh as de-facto international recognition of its claim.

Thailand sent troops into the disputed territory last week when Cambodian soldiers briefly detained three Thai protesters.

More than 4,000 troops have been deployed around the temple and in the immediate vicinity since July 15, according to local commanders and journalists at the scene.

Domestic politics colours dispute

Hor Namhong made his statement during a meeting with several foreign ambassadors, including some from countries that are permanent members of the security council.

He said the Cambodian ambassador in New York on Monday submitted a request for UN assistance in finding a solution in accordance with international laws.

In both countries, the dispute is spilling over into domestic politics.

Supporters of Thailand's opposition are accusing the newly elected government in Bangkok of being too lenient on Cambodia, and some regional analysts believe the powerful Thai military supports that view.

The row has become an election issue in Cambodia, where voters go to the polls next Sunday.

All Cambodian political parties support a tough stance against Thailand, up to and including a military response.

With files from the Associated Press