Handout photo taken and released by the Extraordinary Chamber in the Courts of Cambodia (ECCC) on August 7, 2014 shows former Khmer Rouge leader "Brother Number Two" Nuon Chea in the ECCC courtroom in Phnom Penh
Two Khmer Rouge leaders were jailed for life Thursday after being found guilty of crimes against humanity, the first sentences against top figures of a regime responsible for the deaths of up to two million Cambodians.
Neither "Brother Number Two" Nuon Chea, 88, nor former head of state Khieu Samphan, 83, betrayed any hint of emotion as the sentences were handed down at Cambodia's UN-backed tribunal.
But outside the court on the outskirts of Phnom Penh, regime survivors burst into applause with many weeping after a 35-year wait for justice.
Judge Nil Nonn said the defendants, who are the most senior surviving Khmer Rouge leaders, were "guilty of the crimes against humanity of extermination... political persecution, and other inhumane acts".
Their lawyers swiftly announced their intention to appeal the conviction, but the court earlier ruled the pair would remain in detention until a final judgement due to "the gravity of the crimes".
Prosecutors had sought the maximum life terms for the men, who played key roles in a regime that left around a quarter of the country's population dead during the "Killing Fields" era from 1975-1979.
Led by "Brother Number One" Pol Pot, who died in 1998 without ever facing justice, the Khmer Rouge dismantled modern society in their quest for an agrarian utopia.
Regime atrocities affected virtually every family in Cambodia as Pol Pot's peasant army -- infamous for their red chequered scarves and dark clothing -- slaughtered perceived enemies of the revolution and emptied towns and cities at gunpoint to work in the fields.
The plan spectacularly backfired, leading to the collapse of the economy and mass starvation.
Nuon Chea, wearing his trademark sunglasses, sat in a wheelchair in the dock as the verdict was read, while Khieu Samphan stood impassive next to him.
Late in their two-year trial both men expressed remorse for the suffering the Khmer Rouge inflicted on Cambodia, but remained staunch in denying knowledge of its crimes at the time.
- Justice at last -
The ruling is likely to bring a level of relief to those who survived the Khmer Rouge years, which saw Cambodians wiped out by starvation, overwork, torture or execution by ruthless cadres.
"This is the justice that I have been waiting for these last 35 years," said Khieu Pheatarak, one of around 900 Cambodians at the court to hear the verdict.
Pheatarak was among hundreds of thousands forced from their homes in the capital in 1975 by gun-toting cadres.
"I will never forget the suffering but this is a great relief for me. It is a victory and an historic day for all Cambodians," said the 70-year-old who lost 20 family members including her husband and five siblings under the regime.
The complex case against Nuon Chea and Khieu Samphan was split into a series of smaller trials in 2011 for reasons including their advanced age and the large number of accusations.
US Secretary of State John Kerry in a statement hailed the verdict as "a historic, if long delayed, step along the path for Cambodia" and said the United States would keep supporting work by the UN-backed tribunal.
Social justice campaigners welcomed the verdict as a clear sign to ordinary Cambodians that all are equal before the law.
It shows "that even people in very high positions of power are subject to the rule of law... even if it takes a very long time", said Heather Ryan, a trial monitor at the Open Society Justice Initiative.
However, many victims fear the ageing Khmer Rouge leaders may not live to serve much time in jail -- if their sentences are upheld.
A court spokesman said the entire appeal process could take around 18 months.
Former foreign minister Ieng Sary died aged 87 last year while still on trial. His wife Ieng Thirith was released in 2012 after being ruled unfit for trial due to poor health.
Considered one of the regime's chief architects, Nuon Chea "planned, ordered, instigated, aided and abetted" extermination and forced evacuations according to the trial judge.
Khieu Samphan was found guilty of the same with the exception of ordering the crimes.
Nuon Chea was Pol Pot's deputy but after the fall of the regime he joined rebels in the forested Thai-border area, eventually defecting to the government along with Khieu Samphan in 1998.
Last week a second trial of the pair began at the court on charges including genocide of Vietnamese people and ethnic Muslims, forced marriages and rape.
In its breakthrough first verdict in 2010, the court sentenced former prison chief Kaing Guek Eav, better known as Duch, to 30 years in prison -- later increased to life on appeal -- for overseeing the deaths of 15,000 people.