It might be the last time Cambodians hear the words of the elderly men prosecutors say were most responsible for the deaths and suffering of millions under the Khmer Rouge’s 1970s Killing Fields rule.

There were no last-ditch pleas for forgiveness from the two defendants, the right-hand men of the late Khmer Rouge leader Pol Pot, who protested their innocence in their final arguments before a UN-backed court hoping to deliver justice before the accused die, or donors’ funding dries up.

‘Brother Number Two’ Nuon Chea, 87, and former president Khieu Samphan showed no emotion on Thursday when delivering statements to the people they are accused of betraying when they ruled from 1975 to 1979, when Cambodia was turned into a virtual slave labour camp in which as many as 2.2 million died of disease, starvation, torture and execution.

Khieu Samphan, 81, insisted he was a leader without power, who took no decisions that resulted in atrocities. He said he was paying the price for being close to Pol Pot.

“For the presumption that I am a monster... you seem to believe that I am guilty. All of you believe that I should have foreseen what would happen,” he said, his eyes fixed on a sheet of paper in front of him.

“To date, everyone wants only one thing from me – my admission of guilt on the charges of crimes that I never ever committed, at all.

“Whatever I did was to protect the weak, uphold the respect for fundamental rights and to build a Cambodia that was strong, independent and peaceful,” he said.

Chea and Samphan are the only two defendants left in the complex case 002, which initially had four, charged with crimes against humanity and genocide, among other offences.

Former foreign minister Ieng Sary, who was educated in France, like Pol Pot, Samphan and other Cambodian communist leaders, died this year and his wife, former social affairs minister Ieng Thirith, was diagnosed with Alzheimer’s and declared unfit for trial.

The two face a maximum sentence of life in prison.

To secure a conviction speedily, the prosecution has been split into smaller cases and no time frame has been set for other charges.

The court is trying the pair for their role in the forced evacuation of Phnom Penh in 1975 and the execution of government troops.

A verdict is due in the first half of 2014.

Chea is in poor health and has often been unable to attend proceedings. He expressed remorse for the victims of the Khmer Rouge and said he had no real power in the regime.

Sitting in a wheelchair, he accepted “moral responsibility”, but pled innocence before a court he said had insufficient evidence to convict him.

“The proceeding that have been conducted here are just for the sake of completing the procedure or making it look good in the eye of the public,” he told the tribunal and a packed public gallery of Cambodians behind a glass partition.

“I taught people to love and serve the country... I never educated or instructed anyone to mistreat or kill people.”

The hybrid UN-Cambodian tribunal spent $173 million from 2006-2012 and is struggling to secure funds for further trials.

Investigations are underway into other Khmer Rouge members, but there have been no new indictments.

It has reached a verdict in just one case, case 001, a life sentence in 2010 for Kaing Guek Eav, alias ‘Duch’, chief of the S-21 torture centre where 14,000 people were interrogated before being killed.

International prosecutor Nicholas Koumjian said fast-tracking case 002 was crucial to ensure Duch was not the only conviction.

“It’s not good that we’re having justice 38 years after the event,” he told reporters.

“The choice now is to have it now or never. We have the opportunity now, which is fast disappearing and we have to take advantage of it.”

Three foreign judges have resigned from the tribunal, two citing political interference.

Prime Minister Hun Sen, himself a junior Khmer Rouge officer who defected to Vietnam during their rule, opposed a broader trial of more old leaders.

The Khmer Rouge, for years backed by China and recognised by the West during the Cold War, was finally defeated in 1998, months after Pol Pot died after being purged by his comrades.

Hun Sen has warned that going after more Khmer Rouge leaders could rekindle war.