During his trial on charges of genocide, former Khmer Rouge leader Nuon Chea blamed thousands of Cambodian deaths on the invading Vietnamese army.

Nuon, a trusted deputy of the overall leader Pol Pot told the court in Phnom Penh the Khmer Rouge weren't "bad people," a report by the BBC said.

"I don't want the next generations to misunderstand the history," he said. "I don't want them to misunderstand that the Khmer Rouge are bad people, are criminals. Nothing is true about that."

Nuon, 85, is on trial along with Khieu Samphan, the Khmer Rouge's former head of state, and Ieng Sary, the former Khmer Rouge foreign minister.

A fourth defendant, Ieng Thirith, wife of Ieng Sary and minister for social affairs in the regime, isn't on trial. Judges ruled last month before the trials began that she was suffering with what appeared to be Alzheimer's disease and the charges against her would be stayed.

Thirith, who was arrested in 2007, remains in detention pending a final decision within 15 days by the Supreme Court Chamber on her status. But she could be released this week, a report in The Phnom Penh Post newspaper said.

I am strongly confident that she will be freed as there is not any evidence to keep her in detention," Phat Pouv Seng, Thirith's legal counsel, told the Post.

"If she is released, she can go wherever she wants, maybe to her house in Phnom Penh, or she can go to live with her children in Pailin province."

But Lars Olsen, the legal affairs spokesman for the tribunal, said the Supreme Court Chamber could take longer if it wishes.

"The 15 days is due to elapse this week," he said. "But if there are exceptional circumstances, the Supreme Court Chamber can take longer to issue a decision."

Thirith's husband, Sary, refuses to testify.

Sary, Samphan and Nuon deny the charges stemming from the brutal regime in Cambodia in the late 1970s.

Last month at the beginning of the trials, Nuon blamed "unruly elements" within the Khmer Rouge's Maoist regime, which is blamed for an estimated 1.7 million civilian deaths.

At his first appearance last month, Nuon told the U.N.-backed court he had nothing to do with the deaths. He also denied involvement in torture, saying he was serving the nation to protect it from foreigners.

"My position in the revolution was to serve the interests of the nation and people," he said during his 90-minute opening speech in the court.

Nuon, as deputy leader to Pol Pot, was known as Brother Number Two and oversaw the Year-Zero plan, a mass migration of people from cities to work as peasants on communal farms in the countryside.

The policy included the abolition of money and private property, as well as banning religion in the country they called Democratic Kampuchea.

The result was the starvation and death by disease of an estimated several million people in what became known as the Killing Fields. Thousands more were jailed in Phnom Penh's Tuol Sleng Prison, called S21 and known for brutal torture.

In the end, it was an invading Vietnamese army that overthrew the regime whose leaders and cadres, including Pol Pot, fled into the jungle where they remained for years.