For the first time, two leaders of the brutal Khmer Rouge regime in Cambodia have been found guilty of genocide.

Nuon Chea, 92, was the loyal deputy of regime leader Pol Pot, and Khieu Samphan, 87, was head of state.

They were on trial at the UN-backed tribunal on charges of genocide against Cham Muslims and ethnic Vietnamese.

The guilty verdict is the first official acknowledgement that what the regime did was in fact genocide as defined under international law.

The two men - already serving life sentences for crimes against humanity - have again been sentenced to life.

They are two of only three people ever convicted by the tribunal.

Up to two million people are thought to have died under the brief but brutal Khmer Rouge regime between 1975 and 1979.

Many of them succumbed to starvation and overwork, or were executed as enemies of the state, as Pol Pot tried to turn the country into an agrarian utopia.

Judge Nil Nonn read out the lengthy and much-anticipated ruling to a courtroom full of victims of the Khmer Rouge.

The men were found guilty of a long list of additional crimes, forced marriages, rape and religious persecution.

But the landmark moment in the ruling came when Nuon Chea was found guilty of genocide for the attempt to wipe out Cham Muslims and ethnic Vietnamese Cambodians, and Khieu Samphan was found guilty of genocide against the Vietnamese.

Who were the Khmer Rouge?

Led by Saloth Sar, better known as Pol Pot, the Khmer Rouge was radical Maoist movement founded by French-educated intellectuals.

They sought to create a self-reliant, agrarian society: cities were emptied and residents forced to work on rural co-operatives. Many were worked to death while others starved as the economy imploded.

During the four violent years they were in power from 1975 to 1979, the Khmer Rouge tortured and killed all those perceived to be enemies - intellectuals, minorities, former government officials - and their families.

That included people from ethnic minorities but largely their own people, ethnic Khmers.

The scale and brutality of the killings - meticulously documented by officials - means the regime remains one of the bloodiest of the 20th Century.

The regime was defeated in a Vietnamese invasion in 1979. Pol Pot fled and remained free until 1997, and died under house arrest a year later.

•Credit (except headline) courtesy of BBC.

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