'The first thing is how to maintain Cambodia's national reconciliation and the second is how to make an international effort most useful for the Cambodian people.' His comments marked the first time China has confirmed thoughts of a veto after weeks of speculation following the surrender of Pol Pot's former president, Khieu Samphan, and his ideological chief, Nuon Chea.

International pressure is mounting for both men to be tried along with former foreign minister Ieng Sary and military commander Ta Mok for crimes against humanity following a murderous four-year rule from March 1975.

Khieu Samphan and Nuon Chea are now understood to be living in a stronghold near the Thai border in Pailin, a gem-rich haven for Khmer Rouge defectors under the leadership of Ieng Sary.

Only Ta Mok remains at large, protected by a tiny team of elite fighters.

Both China and Thailand have so far publicly avoided direct involvement, saying only that the matter should be settled by Cambodians.

But a string of other countries led by the US have openly demanded a UN-sponsored trial, and a study headed by former Australian governor-general Sir Ninian Stephan is expected to be complete later this month.

Diplomats believe both Beijing and Bangkok could be deeply embarrassed by any tribunal, given their extensive support of the movement.

China had more than 2,000 advisers in Cambodia during much of the Khmer Rouge's ultra-Maoist experiment in government. It also sustained them with arms and equipment through Thailand once Vietnam had driven them from power 20 years ago.

Cambodian Prime Minister Hun Sen, on the second day of a visit to Malaysia to drum up investment, said the recent defections showed 'national reconciliation had reached its final stage'.

Now, he said, 'development and the economy are the priorities of the Government and the primary aspiration of the Cambodian people as a whole. Everyone wants to lead an adequate life, free from poverty caused by wars, genocidal regimes, national divisions and outside interference'.