A senior UN official said the civilian death toll from the Sri Lankan government's crushing of the Tamil Tiger insurgency was "unacceptably high" and should be the subject of an official inquiry.
Sir John Holmes, the head of the UN office for the coordination of humanitarian affairs (OCHA), said many thousands of people had died in the final days of the government offensive, and accused the Sri Lankan army of using heavy weapons on a coastal strip that was supposed to have been a no-fire zone.
"When there are allegations of this kind, allegations on both sides, they need to be looked into, they need to be investigated," Holmes said. "We had hoped that the [UN] Human Rights Council would look into this, but as you know they took a different path."
On Wednesday, the council voted in Geneva to uphold a resolution put forward by the Sri Lankan government congratulating it on its military victory, sparking outrage from western countries.
One UN official, who did not wish to be named, noted that the council had approved an investigation into civilian deaths caused by the Israeli army offensive in Gaza at the beginning of the year.
"Gaza is a very good comparison. TV was there all the time. Sri Lanka could easily be 10 times worse but there were no cameras. The world wasn't there to see," the official said. The Colombo government restricted press access to the war zone throughout its offensive.
"There is no appetite for such an enquiry among some member states," Holmes said.
The UN high commissioner for human rights, Navi Pillay, has said she is still prepared to pursue an investigation of the alleged atrocities, but would require the approval of the Sri Lankan government - an unlikely event. The Tamil Tigers used suicide bombers and have been accused of using civilians as human shields.
Asked about a report in the Times claiming 20,000 civilians may have been killed in the final throes of the campaign, Holmes denied it was based on UN figures. "The truth is we simply don't know. It doesn't reflect any estimate we made for ourselves. We did have our own internal estimate until the end of April. After that, we didn't have anyone on the ground," the British diplomat said.
The UN estimated death toll to the end of April was 7,000, officials have said. The Times estimate was based on the assumption that a further 1,000 civilians had been killed on average each day until 19 May, when the Tamil Tiger leader, Velupillai Prabhakaran, was killed.
"We do know the death toll was unacceptably high," Holmes said. "There were several thousand dead, and there was an obligation of the government of Sri Lanka to use every possible restraint. There was a no-fire zone in which they said they were not using heavy weapons, and we believe they were."
On 19 May, the Guardian carried a report from one health worker who estimated that 15,000 people might have died in the last four months of fighting. Questions remain about what happened to the wounded who were in a makeshift hospital when medical staff fled. Neither the UN nor the Red Cross could account for them . Doctors working in the no-fire zone have been detained for allegedly exaggerating casualty numbers.
The Red Cross said yesterday it was still not being given access to the war zone, hindering efforts to pave the way for a return home for the estimated 300,000 people who fled the fighting.
Holmes, who visited the government-run refugee camp at Menik Farms at the weekend, said conditions there were "not brilliant but acceptable". He added: "Our bigger concern is the nature of the camps. They are militarised and people are not allowed in or out." The Sri Lankan government has said the camps will be handed over to civilian authority, but not when.