GENEVA (AP) ― A United Nations panel said Wednesday that Libyan government forces have committed crimes against humanity and war crimes in a conflict it estimates has killed between 10,000-15,000 people.

The U.N. investigators found evidence that opposition forces also committed “some acts which would constitute war crimes,” the global body said.

“The commission is not of the view that the violations committed by the opposition armed forces were part of any ‘widespread or systematic attack’ against a civilian population such as to amount to crimes against humanity,” it added.

The three-member panel based its finds on interviews with 350 people in government and rebel-held parts of Libya, as well as in refugee camps in neighboring countries.

Their 92-page report adds to evidence collected by prosecutors at the International Criminal Court, who are seeking arrest warrants for Moammar Gadhafi and two other senior officials it alleges are responsible. The report was commissioned in February by the U.N. Human Rights Council, which has no power to launch legal proceedings but can censure governments accused of committing abuses.

The U.N. panel said government forces committed murder, torture and sexual abuses “as part of a widespread or systematic attack against a civilian population” before and during the conflict.

“Such acts fall within the meaning of ‘crimes against humanity,”’ it said.

The panel also found “many serious violations of international humanitarian law committed by government forces amounting to ‘war crimes.”’

“The consistent pattern of violations identified creates an inference that they were carried out as a result of policy decisions by Col. Gadhafi and members of his inner circle,” it said.

The panel’s report also found that rebel forces committed “some acts which would constitute war crimes.”

Meanwhile, the panel said estimates of the number of people killed in the conflict since February range from 10,000-15,000, citing government officials, the opposition and non-governmental organizations.

The panel also investigated allegations that NATO airstrikes in Libya have caused large numbers of civilian casualties. The alliance has conducted thousands of airstrikes as part of its U.N. mandate to enforce a no-fly zone and protect civilians in Libya.

The experts said they were unable to confirm Libyan government claims that 500 civilians have died in the airstrikes.

“The commission has not seen evidence to suggest that civilian areas have been intentionally targeted by NATO forces, nor that it has engaged in indiscriminate attacks on civilians,” it said.

The panel was led by Cherif Bassiouni, a professor of law at DePaul University in Chicago. Bassiouni, an Egyptian, was assisted by Jordanian jurist Asma Khader, and Canadian Philippe Kirsch, a former judge at the International Criminal Court in The Hague, Netherlands.

That court’s prosecutor, Luis Moreno-Campo, has previously said he has “strong evidence” of crimes against humanity committed by Gadhafi’s regime.

Last month, Moreno-Campo asked judges to issue arrest warrants for Gadhafi, his son Seif al-Islam Gadhafi and intelligence chief Abdullah al-Sanoussi, accusing them of committing crimes against humanity by targeting civilians in a crackdown against rebels.

The U.N. experts called on both sides to conduct transparent and exhaustive investigations and bring those responsible for abuses to justice.