NATO chief, left, has said that members of the alliance are free to give further security aid to Libya individually [AFP]

NATO has formally announced the end of its military campaign in Libya, seven months after launching an air and sea operation under a UN Security Council mandate to protect civilians there.

"It's great to be in Libya, free Libya," Anders Fogh Rasmussen, the NATO secretary general, told a media conference in the capital Tripoli.

"At midnight tonight a successful chapter in NATO history will come to an end. You have already started writing a new chapter in Libya's history," he said.

"We acted to protect you. Together we succeeded. Libya is finally free, from Benghazi to Brega, from Misrata to the Western Mountains and to Tripoli.

"We discussed the successful mission that NATO and partners conducted over last seven months to save people of Libya." Rasmussen said he was proud of the part NATO had played in the uprising against Muammar Gaddafi's 42-year old rule.

Mustafa Abdul Jalil, the NTC chairman, thanked Rasmussen for the successful operation on the behalf of the Libyan people.

"Today, we have achieved victory by the grace of God and a resolution has been handed to put an end to NATO operation by midnight," Jalil said.

Rasmussen told Al Jazeera that members of the alliance were free to give further security aid to Libya individually.

Costly venture

The secretary general had announced last week that mission would end on Monday, calling it "one of the most successful" operations in the history of the 62-year-old alliance.

NATO stuck to its decision to end the operation despite NTC requests for it to stay engaged longer and some analysts have said it could have assisted in the transition to democracy by helping with security sector reform.

NATO took over the mission on March 31, based on a UN mandate [Resolution 1973] that set a no-fly zone over Libya and permitted foreign military forces, including NATO, to use "all necessary measures" to protect Libyan civilians.

The alliance's members have been keen to see a conclusion to a costly effort that has involved more than 26,000 air sorties and round-the-clock naval patrols at a time when budgets are under severe strain due to the global economic crisis.

Fourteen NATO members and four other states provided naval and air forces, but only eight NATO nations took part in combat missions. Some large NATO states, notably Germany, had opposed the intervention.

Non-NATO member Qatar played a major role in the entire mission and helped extensively in humanitarian operations.