A United Nations team has begun arriving in Cambodia to investigate the possibility of bringing to trial leaders of the Khmer Rouge movement alleged to be responsible for the killing of more than one-million of their countrymen.

The team, led by an Australian judge, Sir Ninian Stephen, is to spend more than a week in the country studying the evidence of atrocities known as the killing fields during the Khmer Rouge's four-year rule in the 1970s, including executions, torture and forced migrations.

The three-man U.N. panel was appointed in response to a request by the Cambodian government for help in setting up a tribunal.

The former Khmer Rouge leader, Pol Pot, died in a rebel-held village earlier this year, after being detained and denounced by his own followers.

But other Khmer Rouge leaders have defected to the government or remain at large.