The genocide trial of two former Khmer Rouge leaders resumed Friday at a UN-backed court in Cambodia, where they face charges over the mass murder of Vietnamese people and ethnic Muslims, forced marriage and rape.
Nuon Chea, 88, known as "Brother Number Two", and ex-head of state Khieu Samphan, 83, have already been given life sentences after a separate trial at the same court in August for crimes against humanity.
That ruling saw them become the first top figures to be jailed from a regime responsible for the deaths of up to two million Cambodians from 1975-1979.
The second trial, which opened in July, got under way Friday with judge Nil Nonn reading out the charges against both suspects of genocide, crimes against humanity and war crimes.
Nuon Chea, wearing his trademark sunglasses, and Khieu Samphan sat in court alongside their defence teams as around 300 survivors of the regime protested outside, demanding monetary compensation for their suffering.
The complex case against the pair was split into a series of smaller trials in 2011 to get a faster verdict given the vast number of accusations and their advanced age.
Both men have appealed their August convictions, which followed a two-year trial focused on the forced evacuation of around two million Cambodians from Phnom Penh into rural labour camps and murders at one execution site.
The second trial, broader in scope than the first, is viewed as an opportunity for many other victims of the regime to seek redress.
"The accused will now face trial for the biggest crimes for which they have been indicted," said prosecutor Chea Leang in an opening statement. "This court cannot be closed until justice is done for the victims of these crimes."
Khieu Samphan told the court he would make a brief statement, while Nuon Chea said he would not answer any questions.
The testimony by the prosecution's first witness, originally scheduled for Monday, has been postponed until 27 October.
- 'Heinous' crimes -
The mass killings of an estimated 100,000 to 500,000 ethnic Cham Muslims and 20,000 Vietnamese form the basis of the genocide charges against the pair.
Before these charges were filed, the treatment of the minority Muslim group and Vietnamese community was rarely discussed.
"The ways in which the Khmer Rouge mistreated us is too heinous to describe in words. Their goal was to exterminate our race," said Seth Maly, a 64-year-old Cham labour camp survivor who lost 100 of her relatives, mostly through execution, during the regime -- including her two daughters, parents and five siblings.
Nuon Chea and Khieu Samphan also face charges of crimes against humanity and war crimes in the second trial -- for the deaths of up to two million people through starvation, overwork or execution during the communist regime.
Most of these deaths do not fall under the charge of genocide, which is defined by the United Nations as "acts committed with intent to destroy, in whole or in part, a national, ethnic, racial or religious group".
"Without a second trial, there would be an enormous gap in the legal record about crimes that defined the experience of -- and still traumatise -- regime survivors," said Anne Heindel, a legal adviser to the Documentation Center of Cambodia which researches the country's bloody history.
Led by "Brother Number One" Pol Pot, who died in 1998, the Khmer Rouge dismantled Cambodian society in a bid to create an agrarian utopia.
The hearings will also provide the first forum for justice for tens of thousands of husbands and wives forced to marry, often in mass ceremonies, as part of a Khmer Rouge plan to boost the population.
The rape charges refer to rape within the forced marriages.
A court spokesman has estimated the trial may go on until 2016, with hearings covering crimes committed at Khmer Rouge labour camps and prisons including the notorious Tuol Sleng, also known as S-21.