NATO defense ministers are meeting Wednesday in Brussels to discuss the alliance's ongoing mission in Libya, the war in Afghanistan and efforts to acquire necessary resources as members face budget cuts.

Ahead of the talks, U.S. Secretary of Defense Leon Panetta said NATO members must work more closely than ever, and warned it is wrong to assume the United States will make up for financial shortfalls. He said the Pentagon is facing $450 billion in cuts over the next 10 years, and could face additional cuts that would be “devastating” to security in the U.S. and abroad.

Panetta said the fall of former Libyan leader Moammar Gadhafi is an example of why NATO matters, as alliance warplanes continue to carry out airstrikes against Gadhafi loyalists.

NATO Secretary-General Anders Fogh Rasmussen has called the mission a “great success,” but both he and Panetta say it has exposed shortcomings in surveillance, intelligence and air-to-air refueling capabilities.

Panetta says members must coordinate and pool their limited resources amid widespread budget cuts.

The defense ministers will also address progress in Afghanistan, where troops in the U.S.-led NATO coalition began transferring security responsibility in some areas to Afghan forces in July. All combat troops are scheduled to leave the country by the end of 2014, and Rasmussen said Monday he expects the next phase of the transition to be announced soon.

He said there has been “significant” progress in Afghanistan, and that NATO military officials say the insurgency there has been weakened.

Panetta said Tuesday that General John Allen, the commander of U.S. and NATO forces in Afghanistan, lacks the trainers that are “critical” to this phase of the transition.

The meeting is also expected to include discussion of Kosovo, where NATO peacekeepers clashed last week with ethnic Serbs at a Kosovo-Serbia border crossing.