The latest hostilities, which lasted for less than an hour, followed heavy fighting on Sunday after the collapse of a ceasefire agreed a day earlier in the wake of the worst clashes between the two neighbours in years.

In New York, Ban Ki-moon's office said the UN chief was "deeply concerned" about the standoff. "The secretary-general appeals to both sides to put in place an effective arrangement for cessation of hostilities and to exercise maximum restraint," it said, in a call echoed by China and Singapore.

Maria Luiza Ribeiro Viotti, the Brazilian ambassador who is president of the UN Security Council for February, said its members would be willing to meet to discuss the dispute.

Cambodian Prime Minister Hun Sen has warned that regional stability was at risk from what he described as "Thailand's aggression". He asked for UN troops to be sent to the area to create a "buffer zone" and said he would welcome help from allies in the Association of Southeast Asian Nations (ASEAN) to resolve the dispute.

The World Court ruled in 1962 that Preah Vihear itself belonged to Cambodia, although its main entrance lies in Thailand.

AFP