Cambodian Prime Minister Hun Sen has lashed out at the United Nations for failing to act against Cambodia's former Khmer Rouge regime when it was committing genocide.

Mr. Hun Sen Thursday said in a speech that the United Nations remained virtually silent when as many as two million Cambodians died from starvation, overwork and execution between 1975 and 1979.

Mr. Hun Sen said Wednesday that a U.N. envoy who criticized Cambodia's human rights record was no longer welcome in the country.

He said that U.N. Secretary-General Kofi Annan should remove Yash Ghai as special U.N. envoy for human rights in Cambodia.

Tuesday, Ghai said that power in Cambodia is concentrated around Mr. Hun Sen and that little has been done to improve human rights in Cambodia under his rule.

Several of Hun Sen's critics were jailed on defamation charges in recent months after accusing the Cambodian leader of ceding land to Vietnam in a controversial border agreement.

They have since been released following domestic and international condemnation.

Some information for this report was provided by AFP and AP.