53 bodies of pro-Gaddafi supporters have been found in a hotel in the Libyan city of Sirte. According to Human Rights Watch, the men were apparently executed.
The organization Human Rights Watch (HRW) said the victims - some had their hands tied - died last week.
The new leaders of Libya has denied any involvement in the alleged executions and urged Libyans to give up revenge.
The discovery comes a day after the jubilant crowds took to the streets across the country to celebrate the announcement of the national liberation by the interim government.
An announcement that occurred three days after the death of Muammar Gaddafi.
Libyan leader Mustafa Abdul Jalil said the National Transitional Council (CNT) formed a committee of inquiry to clarify the circumstances of the death of Colonel Gaddafi.
Some accuse the troops of the CNT to have executed after his capture in Sirte.
The bodies of fighters loyal to Gaddafi were found Sunday on the lawn of an abandoned hotel in Sirte, a place that has seen heavy fighting last week in the last battle for control of the city.
"Some had their hands tied behind their backs when they were shot, said Peter Bouckaert, emergencies director at Human Rights Watch said in a statement. This requires the immediate attention of the Libyan authorities to investigate what happened and prosecute those responsible. "