|The Sri Lankan army is accused of heavy-handedness in its fight against the Tamil rebels [Getty Images]
A UN panel said that "tens of thousands" of deaths in the Sri Lankan government's final 2009 offensive against Tamil separatists may amount to war crimes.
In a 200-page report released on Monday, the three-member panel estimated that some 40,000 civilians were killed in the civil war--the first UN estimate of the death toll.
Ban Ki-moon, UN secretary-general, said he would only launch an international investigation into allegations of possible war crimes if the government agreed, which is highly unlikely.
A UN statement publicly releasing a report by a UN panel said the secretary-general had been advised that he needed government consent or a decision from member states in an international forum.
He did not specify a forum, but it could include the UN Security Council, General Assembly or Human Rights Council.
Speaking to Al Jazeera, Donald Gnanakone, president of Tamils for Justice, said that "As UN secretary general, he should not abdicate his responsibilities on war crimes and crimes against humanity.
"As many as 100, 000 innocent Tamil civilians were killed, 60, 000 were injured and 310, 000 were incarcerated under inhuman and cruel conditions."
Ban Ki-moon has decreed an inquiry into United Nations' actions during the conflict following criticism by the panel.
The UN panel was set up following a visit by Ban to Sri Lanka, shortly after the end of the conflict.
Al Jazeera's Kristen Saloomey, reporting from UN headquarters in New York, said that the report also criticised the UN "for failing to protect civilians" by reporting the death toll during the waning days of the war.
"If the UN had been forthcoming in providing death toll during the war, perhaps lives could have been saved," Saloomey said.
She added that Ban was trying to use the report as a leverage against the Sri Lankan government, so that it would permit full-fledged investigation into the conflict, "but it appears that no deal was reached."
War crimes denied
The Sri Lankan government criticised the move as "an unwarranted and unnecessary interference with a sovereign nation".
The UN group's official mandate called on it to examine "the modalities, applicable international standards and comparative experience with regard to accountability processes" relating to the final stages of the conflict in Sri Lanka.
Government forces defeated the Liberation Tigers of Tamil Eelam (LTTE) in May 2009 after a quarter-century conflict that killed thousands of people. The end of the war displaced large numbers of people in the north of the island state.
Sri Lanka's government denies any war crimes were committed, but human-rights groups say the government and the Tamil Tigers, who were seeking to set up a separate Tamil state, were guilty of rights violations.
Sri Lanka set up its own Lessons Learnt and Reconciliation Commission (LLRC), which human-rights groups have said lacks credibility and impartiality. The commission is due to report to the government next month.
A Sri Lankan government spokesman said last December the UN panel "will be given visas only to testify before the LLRC if they request [that] and not for any investigations".
UN officials said they understood that because of that restriction, the UN panel had not visited Sri Lanka.
In a statement last week, Human Rights Watch, the New York-based rights monitor, said that almost two years after the war, Sri Lanka had "taken no steps to hold anyone on either side of the conflict accountable for serious violations of international law".
Brad Adams, Asia director for Human Rights Watch, praised Ban's decision to make the report public, saying it "will help move justice forward in Sri Lanka".