The U.N.-backed tribunal in Cambodia has set a November 21 date for the beginning of major trial proceedings against the top four surviving Khmer Rouge leaders.

The tribunal said Tuesday that the proceedings will begin that day with the reading of charges against the four — including nominal Khmer Rouge head of state Khieu Samphan. The prosecutors will then have two days to make their opening statements.

The defendants are charged with genocide, crimes against humanity and war crimes in the deaths of up to 2 million people between 1975 and 1979.

The tribunal began hearing preliminary motions in the case in June. Last month, it decided to speed up proceedings by dividing the complex charges into segments.

Tuesday's tribunal statement said the November 21 proceedings will provide a general foundation for all charges against the accused, including those which will be prosecuted in later trials.

In addition to defendant Samphan, the accused are Nuon Chea, described as the regime's chief ideologue, Khmer Rouge Foreign Minister Leng Sary and his wife, Leng Thirith. All deny the charges.

Khmer Rouge leader Pol Pot died in 1998.

A court spokesman last month said the decision to split up the charges means the court will hand down separate verdicts on each charge as the trial proceeds.

Observers say if all the charges were tried at once, it could take as long as a decade to produce a verdict. All of the defendants are already elderly and there is some doubt whether all would live that long.