A former Khmer Rouge leader branded his conviction for crimes against humanity a "child's fairy tale" at a UN-backed court in Cambodia Friday, as he faced further charges of genocide, forced marriage and rape. Nuon Chea, 88, known as "Brother Number Two", has already been given a life sentence along with ex-head of state Khieu Samphan, 83, 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. At his genocide trial Friday, Nuon Chea spoke in court for the first time since the convictions to accuse judges of ignoring his evidence in August. "You presented a story that was simple but ultimately just a child's fairy tale... you made a bitterly disappointing mockery of justice," he said, reading a statement from the dock. The ex-leader also called for the judges to be disqualified and his defence team to boycott further hearings until a decision on the subject is made. The complex case against Nuon Chea and Khieu Samphan 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. Khieu Samphan also made a statement to the court Friday, claiming his right to a fair trial had been violated. "I know in advance that you will find me guilty and you will convict me eventually even with the current trial," he said. As prosecutors made their opening statements in the trial, which opened in July, around 300 regime survivors protested outside court, holding placards demanding monetary compensation for their suffering -- there are no individual financial reparations under the court's rules. 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. Laying out the charges, co-prosecutor Nicholas Koumjian told the court the ex-leaders committed the alleged crimes "systematically... to maintain their own power". The testimony by the prosecution's first witness, originally scheduled for Monday, has been postponed until 27 October. - 'Extermination was the goal' - 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 -- 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 Cambodians 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, an 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, with the prosecution alleging that every incident of involuntarily sexual intercourse within these marriages constitutes a crime against humanity. 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.