THE HAGUE, Netherlands (AP) — A human rights lawyer is calling on the International Criminal Court to investigate Cambodian authorities and the country’s authoritarian leader, Prime Minister Hun Sen, for what he says is a systematic pattern of crimes to crush dissent and attempts to shield former Khmer Rouge leaders from genocide prosecutions.

American attorney Morton Sklar says the request is based on a “systemic” pattern of attacks on political opponents and what he portrayed as Cambodian government efforts to stymie the work of the United Nations-backed tribunal prosecuting members of the Khmer Rouge regime, whose rule from 1975-1979 left an estimated 1.7 million people dead from starvation, disease, forced labor and executions.

Hun Sen’s administration did not immediately respond to calls seeking comment Thursday.