In this photo released by the Extraordinary Chambers in the Courts of Cambodia, Khieu Samphan, center, former Khmer Rouge head of state, sits in a court room before a hearing at the U.N.-backed war crimes tribunal in Phnom Penh, Cambodia, Friday, Nov. 16, 2018. Picture: Mark Peters/Extraordinary Chambers in the Courts of Cambodia via AP.

Phnom Penh - A UN-backed court on Friday convicted two Khmer Rouge leaders of committing genocide, the first of Pol Pot's cadre to be found guilty for targeting minority groups for elimination during the regime's rule in Cambodia in the 1970s.

Senior cadres Nuon Chea, 92, Khieu Samphan, 87, received their second life sentences, after having been sentenced in 2014 to life in prison for crimes against humanity committed during the ultra-communist regime's rule from 1975 to 1979.

Reading the decision Friday morning, Judge Nil Nonn, the court's trial chamber president, outlined Chea's criminal responsibility for murder, torture and other crimes as "Pol Pot's loyal right-hand man" who "enjoyed oversight of all [communist] party activities" due to his senior leadership position within the regime.

Samphan, the regime's head of state, and Chea, deputy communist party secretary, were both found guilty of genocide against ethnic Vietnamese within Cambodia, crimes against humanity and breaches of the 1949 Geneva Conventions. Chea was also convicted for genocide against minority Cham Muslims.

Some 1.7 million people died from starvation, torture, execution and forced labour under the Khmer Rouge.