TRIPOLI, Libya - A human rights groups says it has discovered 53 decomposing bodies, apparently of Moammar Gadhafi loyalists, some of whom may have been executed by revolutionary forces.

The New York-based Human Rights Watch said Monday that the discovery in Gadhafi's hometown of Sirte "seems part of a trend of killings, looting and other abuses committed by anti-Gadhafi fighters who consider themselves above the law."

The group urged Libyan authorities to rein in armed groups.

The latest discovery of the grave came to light as Libya's new leaders declared the country liberated, following a brutal eight-month civil war. The declaration was overshadowed by continued questions about whether Gadhafi was executed after capture last week.

The U.S. and Britain have called for an investigation.