The United Nations has called for a special court to try war crimes committed during the Sri Lankan army's long conflict with Tamil Tiger rebels.
In a long-delayed report, the UN Human Rights Council accused both sides of atrocities, especially during the final stages of the war in 2009.
The new court would have foreign judges and investigators, the report said. Sri Lanka has resisted such moves.
One UN estimate is that 40,000 Tamils died in the final army offensive.
Earlier this week Sri Lanka's new government unveiled plans to set up a truth and reconciliation commission to examine war crimes allegations, including those against the military.
The previous government of President Mahinda Rajapaksa had resisted international pressure to investigate the issue.
While government forces were accused of indiscriminate shelling leading to massive casualties, the Tamil Tiger rebels were alleged to have used civilians as human shields.
As well as the thousands of Tamils who died, many others are still missing.
Despite promises to pursue accountability, Sri Lanka's new government, elected last month, would be reluctant to hold war crimes trials, correspondents say.
The UN Human Rights Council postponed the planned publication of its report in March, after Mr Rajapaksa lost the presidential election to party rival Maithripala Sirisena in January.
Mr Sirisena, who was a serving government minister during the final stages of the war, promised to co-operate with the UN and to promote reconciliation on the island.
The report called on Colombo to remove from office military and security force personnel and any other officials where there were reasonable grounds to believe they were involved in human rights violations in the 26-year war that ended in 2009.
Former New Zealand High Court judge Dame Silvia Cartwright was one of three Commissioners who assisted with the investigation.