Updated

Libyan oil chief Shukri Ghanem said Wednesday he had defected and now supports the rebels, in a major blow to Libyan leader Muammar al-Qaddafi, news reports said, as NATO and its partners decided to extend their Libya mission for another 90 days.

"In this situation you can no longer work, so I have left my country and my work to unite myself with the choice of young Libyans to fight for a democratic country," the ANSA news agency quoted Ghanem as saying in Rome.

Ghanem said he had left the regime two weeks ago and arrived in Rome on Tuesday. The Italian Foreign Ministry said it had no comment on the report.

For several weeks, Libyan officials had insisted Ghanem, who as head of the National Oil Corp. serves as Libya's oil minister, was on a business trip. As recently as last week, Libya's foreign ministry said he would represent the Qaddafi government at a June 8 OPEC meeting in Vienna.

The defection, the latest in a series, followed the departure of eight top Libyan army officers, including five generals, who were presented to reporters in Rome earlier this week by the Italian foreign ministry days after they fled Libya.

Another 13 servicemen loyal to Qaddafi, including a colonel and four commanders, have fled to neighboring Tunisia, the official Tunisian news agency reported. It was the second group of military men to defect to Tunisia this week.

The latest group arrived Sunday in the port of Ketf in southern Tunisia, the news agency TAP said Tuesday.

Meanwhile in Brussles, NATO and its partners in the military campaign to protect Libyan civilians decided to extend their mission for another 90 days, the military alliance's top official said Wednesday.

"This decision sends a clear message to the Qaddafi regime: We are determined to continue our operation to protect the people of Libya," said NATO Secretary-General Anders Fogh Rasmussen. Qaddafi is trying to withstand the NATO air barrage and put down a rebellion among his own people.

Wednesday's decision came during a meeting of ambassadors from the 28 NATO countries plus ambassadors from the five non-NATO countries participating in the Libya campaign -- Jordan, Qatar, Sweden, the United Arab Emirates and Morocco -- said Carmen Romero, the NATO's deputy spokeswoman.

The military alliance took over command of the operation on March 31 after difficult negotiations among its members. Unanimity of 28 is required for action, and the operations to enforce a no-fly zone and use air power, based on a U.N. Security Council resolution that calls for the protection of civilians, were authorized for an initial 90 days.

That time would have expired June 27. The decision to extend the campaign was taken nearly a month ahead of time to allow the participating countries to do their internal planning, Romero said.

NATO also is enforcing a U.N. arms embargo against Libya. That part of the operation has no time limit.

Critics have charged that the military campaign has turned into a stalemate and said it is difficult to dislodge a government through air power alone. But NATO, while maintaining that regime change is not its goal, says it has significantly diminished Qaddafi's ability to attack civilians.

Fogh Rasmussen said in a statement that the extension of the campaign carries a message not only for Qaddafi but for the Libyan people.

"NATO, our partners, the whole international community, stand with you," he said. "We stand united to make sure that you can shape your own future. And that day is getting closer."

The Associated Press contributed to this report.