FRESH NATO air raids shook Tripoli today as the United Nations accused both Libyan leader Muammar Gaddafi’s regime and rebel forces of committing crimes against humanity in their 15-week conflict.

A series of six blasts at around 12.35am local time were followed by several more a few minutes later in the Libyan capital, the target of NATO air raids on an almost nightly basis.

Libyan Oil Minister Shukri Ghanem, meanwhile, became the latest member of Colonel Gaddafi’s regime to resign, saying in Italy that he had left Libya to join the uprising against his former boss and “fight for a democratic country”.

And on the ground in Libya, a huge car bomb rocked a major hotel today in Benghazi, the Libyan rebels’ capital in the east of the country, but caused no casualties, witnesses and police said.

A commission of inquiry set up by the UN Human Rights Council in Geneva accused Colonel Gaddafi’s regime of carrying out systematic attacks on the population, saying that it committed not only crimes against humanity but also war crimes.

While it found fewer reports of violations by the opposition, the commission also said rebel forces committed acts that constituted war crimes.

The commission has “reached the conclusion that crimes against humanity and war crimes have been committed by the government forces of Libya,” it said in a statement.

“The commission received fewer reports of facts which would amount to the commission of international crimes by opposition forces, however, it did find some acts which would constitute war crimes.”

The 47-member UN Human Rights Council set up the investigation into suspected crimes against humanity in February after Colonel Gaddafi’s regime dispatched Libya’s army and air force to fire on civilians.

Hours after NATO-led aircraft launched new raids on Tripoli today, ambassadors of the military alliance meeting in Brussels decided to renew the mission for another 90 days to late September, giving individual nations time to prepare their contributions.

“This decision sends a clear message to the Gaddafi regime. We are determined to continue our operation to protect the people of Libya,” said NATO Secretary-General Anders Fogh Rasmussen.

“We will keep up the pressure to see it through.”

NATO, whose current campaign expires on June 27, has intensified its air raids in recent weeks with daily strikes on command and control bunkers in Tripoli to prevent Colonel Gaddafi from crushing a revolt that began in mid-February.

Oil minister Ghanem, the head of the state-run National Oil Corporation (NOC), said in Rome that he had joined the rebellion, following weeks of rumors and denials about his defection.

“I can’t work in this situation so I have left my country and my job to join the choice made by young Libyans to fight for a democratic country,” he said as he spoke of a possible “peaceful solution” to the conflict.

Libya’s longtime representative at the OPEC oil cartel said his country was “moving towards a total block on oil production.”

Italy’s foreign ministry denied any role in arranging Ghanem’s presence in the country but welcomed the announcement, after eight Libyan military officers this week announced their defection at a press conference in Rome.

NATO’S Rasmussen said in Brussels that Colonel Gaddafi’s departure is only a question of time.

“The question is not if Gaddafi will go but when,” Rasmussen said. “It could take some time yet but it could also happen tomorrow.”

At a news conference in Tripoli, however, Ibrahim warned the departure of Libya’s veteran leader would be a “worst case scenario” for the country and could trigger “civil war”.

“If Gaddafi goes, the security valve will disappear,” he said.

Two cars were destroyed in the Benghazi explosion in the parking lot of the Tibesti hotel used by rebel leaders, diplomats and journalists, an AFP correspondent said.

The rebels’ Transitional National Council (TNC) blamed the huge car bomb blast on forces loyal to Colonel Gaddafi.

“This act of terrorism shows, once again, the irresponsible and criminal nature of Gaddafi’s regime,” TNC chairman Abdul Jalil said in a statement as he vowed to take “all measures” to bring the perpetrators to justice.

A police officer said a bomb was detonated in one car and the blast damaged a second car parked next to it. There were no immediate reports of injuries.