WASHINGTON (Reuters) - The United States issued a report on Thursday detailing possible atrocities by both sides toward the end of Sri Lanka’s civil war and urged the government to investigate allegations of war crimes.

Children play in a playground at the Settikulam camp for internally displaced people (IDP) in northern Sri Lanka August 15, 2009. REUTERS/Stringer

The State Department report, requested by Congress, recounted allegations of government shelling of civilians during the early months of 2009 as well as charges that Tamil rebels recruited children to fight in the conflict.

The State Department said it did not attempt to verify the individual reports, but found them credible.

“The government of Sri Lanka has said that they are determined to establish a reconciliation process with the people of the north, but we believe strongly that a very important part of any reconciliation process is accountability,” said State Department spokesman Ian Kelly.

“This report lays out some concerns that we have about how this military operation was conducted.”

Sri Lanka’s government declared victory in May in one of the world’s most intractable wars. That followed a series of battles in which government forces killed the leader of the Tamil Tigers, who had been fighting to create a separate ethnic Tamil homeland.

The United Nations said the conflict had killed between 80,000 and 100,000 people in the Indian Ocean country since full-scale civil war broke out in 1983.

The State Department emphasized that the report reached no legal conclusions as to whether the incidents detailed in the report constitute war crimes or other violations of international human rights law.

Catalog OF GRISLY CHARGES

The report covers only 2009 and quotes primary and secondary sources, including media accounts, eyewitnesses, foreign governments and aid groups.

It accuses the LTTE, which Washington has listed as a terrorist groups since 1997, of killing civilians and forcibly recruiting people as young as 12 to fight.

It also offered a grisly catalog of alleged government abuses, including the killing of captives or combatants seeking surrender, the abduction and murder of Tamil civilians, and dismal humanitarian conditions in camps for displaced persons.

Sri Lanka rejected the report’s allegations as “unsubstantiated and devoid of corroborative evidence.” It said LTTE supporters had a long history of fabricating stories to damage the Sri Lankan government’s reputation.

“Thereby these interests hope to fan, once again, the flames of secessionism and to undo the concerted efforts of the government and people of Sri Lanka, for rehabilitation and national reconciliation,” a Foreign Ministry statement said.

The United States called on Sri Lanka to open up areas in the north of the country where the fighting took place so that international organizations could more thoroughly probe the alleged abuses.

“We call on them to develop the kind of mechanisms that can more thoroughly investigate the many allegations laid out in this report and then ultimately, as appropriate, bring justice to those that are found guilty,” said Kelly.

Human Rights Watch said the U.S. report should dispel any doubts that serious abuses were committed during the final months of the 26-year civil war.

“Given Sri Lanka’s complete failure to investigate possible war crimes, the only hope for justice is an independent, international investigation,” Brad Adams, the watchdog group’s Asia director, said in a statement.