The Khmer Rouge revolution in the 1970s was aimed at freeing Cambodia from colonialism and protecting it from invasion by Vietnam, the party's ideologue, Nuon Chea, told a court on Tuesday, opening his defence against a charge of genocide.
The testimony marked the first time a leader of the Khmer Rouge has defended the motives of the ultra-communist regime since the U.N.-backed court started to try cases last year related to the bloody Killing Fields revolution that wiped out a quarter of the population from 1975-1979.
Former President Khieu Samphan, ex-Foreign Minister Ieng Sary and Brother Number Two Nuon Chea are charged with crimes against humanity and war crimes as well as genocide.
Nuon Chea, the first defendant to take the stand, denied all the charges.
My position in the revolution was to serve the interests of the nation and people, he said.
Oppression, injustice compelled me to devote myself to fight for my country. I had to leave my family behind to liberate my motherland from colonialism and aggression, and oppression by the thieves who wished to steal our land and wipe Cambodia off the face of the earth, he told the court.
Vietnam wanted to swallow Cambodia, Nuon Chea said.
The army of the communist party of Vietnam and Vietnam cadres still remain discreetly on Cambodian soil ... with the ambition of occupying, swallowing Cambodia and getting rid of Cambodia, of her race and ethnicity, bringing in Vietnamese immigrants illegally to live in Cambodia to this day.
Prosecutors say as many as 2.2 million people were killed under the Khmer Rouge, which was finally forced from power when Vietnam invaded in 1979.
Remnants of the Khmer Rouge fought on until the 1990s.
Pol Pot, the French-educated architect of the Year Zero revolution, died in 1998.
A fourth defendant, former Social Affairs Minister Ieng Thirith, was declared mentally ill and unfit for trial last week. She remains in detention pending an appeal by prosecutors.
In opening arguments on Monday, Cambodian and international prosecutors said the defendants had masterminded one of the worst horrors in modern history, killing or enslaving millions of people in their creation of a living nightmare.
International co-prosecutor Andrew Cayley told the tribunal it should not be tempted by feelings of compassion for the elderly and infirm defendants in their 80s who had murdered, tortured and terrorised their own people.
Their case is the second to be brought before the Extraordinary Chambers in the Courts of Cambodia (ECCC) and could be the last, with rights groups furious over the court's unexplained rejection of a third high-profile case.
Since its creation in 2005, it has spent close to $150 million and has been mired in controversy, fraught with delay, resignations, allegations of misconduct, apathy and political interference directed at the U.N. and Cambodian authorities.
Many Cambodians lost confidence in the court after its first and only ruling so far, a 35-year jail term, commuted to 19 years, handed down to Kaing Guek Eav.
Also known as Duch, he oversaw the deaths of more than 14,000 people at a torture centre in Phnom Penh. His appeal is set for February 3 next year.
(Writing by Martin Petty and Alan Raybould; Editing by Jason Szep and Jonathan Thatcher)