BRUSSELS - NATO defense ministers meet Wednesday and they are expected to discuss ways of ending the alliance's aerial campaign in Libya and training Afghan security forces for a larger role in their country's war.

U.S. Defence Secretary Leon Panetta, who took over from Robert Gates as Pentagon chief in July, will be making his first visit to Europe in that role to attend the meeting.

The conference will begin with a series of preparatory meetings by allied defence and foreign ministers in the run-up to NATO's summit in May in Chicago.

Ministers have praised the operation in Libya, which enabled Moammar's Gadhafi's opponents to oust his autocratic regime. It has been cited as proof that the Cold War alliance remains relevant to international security.

"Our operation to protect civilians in Libya has been a great success," NATO Secretary-General Anders Fogh Rasmussen said.

NATO warplanes have flown nearly 25,000 sorties, including more than 9,000 strike missions, since the strikes began in March.

European members and Canada provided most of the strike aircraft, but the war exposed shortages in Europe's capabilities in strategic transport, aerial surveillance and air refuelling, which had to be supplied by the U.S.

The campaign also revealed rifts within the Western military alliance. Only eight of the 28 members participated, while the others stayed away -- mostly for fear of how the new mission would affect the alliance's commitment to Afghanistan.

Before stepping down as Pentagon chief, Gates bluntly criticized NATO for what he said were shortages in military spending and political will, warning of "a dim if not dismal future" for the alliance unless European members boosted their participation. But diplomats said Panetta was not expected to continue with such a confrontational attitude.

In Afghanistan, NATO's troops and the government's security forces are still struggling against Taliban insurgents, whom they outnumber by about 15 to 1. Some 130,000 NATO troops are currently fighting in Afghanistan; more than 2,700 NATO troops have died in the war.

High-profile Taliban attacks this year have undermined NATO's claim that it has the upper hand, and the United Nations released a report last month saying the monthly level of violence in the country was significantly higher than in 2010.

The U.S. and NATO began transferring security responsibilities this year to newly trained Afghan forces with the goal of withdrawing all their combat troops by the end of 2014.

Fogh Rasmussen said the transition remains "fully on track" and that Afghan forces are already providing lead security for one-quarter of the population.

"I expect the next stage of transition to be announced soon, and I expect it to be substantial," he said Monday. "And at the same time, our military authorities assess that the insurgency has been weakened overall."

Other issues at the two-day NATO meeting will include the situation in Kosovo, where intercommunal clashes continue nearly 12 years after an alliance bombing campaign ended Serbia's rule there, and anti-piracy patrols off Somalia, stretching into a third year after a three-month authorization period in 2008.

Officials said they want at least one of these three missions -- Libya, Kosovo or Somalia -- to conclude successfully, quickly and for good.

At the top levels of the military alliance there is great eagerness to wrap up the Libyan air campaign as soon as possible, and a reluctance to get involved in nation-building or policing now that Gadhafi has fallen from power.

The NATO meeting agenda also includes an ambitious plan to boost the alliance's capabilities at a time of budgetary belt-tightening through greater pooling and sharing of military resources by NATO's 28 members. The plan calls for achieving initial operational status for the European missile defence systems well.

"Improving our capabilities is not only necessary, it is vital," Fogh Rasmussen said. "We must spend on priorities and spend together, by financing shared projects which make us all safer."