France and Britain proved their military ability in the absence of US leadership in Libya but the European Union and NATO emerged paradoxically weakened, analysts said.

Many had warned them against getting bogged down in an Iraq-style quagmire in Libya but after six months, both Paris and London this week felt vindicated when the operation they led helped rebels topple Moamer Kadhafi's regime.

The intervention mandated by the United Nations and carried out under NATO command "is a success because two major nations took their responsibilities," French Defence Minister Gerard Longuet said earlier this week.

The Libya raids were a watershed because they marked a rare case of the United States shunning the leadership role in a large Western military intervention, leaving France and Britain to fill the vacuum.

"The Brits and the French can rightly claim to have delivered in spite of America taking the backseat," Francois Heisbourg, from the Paris-based Foundation for Strategic Research, said.

But Andre Dumoulin, from the Multidisciplinary Network for Strategic Studies, argued that Washington's role in the aerial bombing campaign that annihilated Kadhafi's military infrastructure was secondary only on paper.

"The Americans did mobilise considerable means when it was required," the analyst said.

He cited cruise missiles early on in the bombing to destroy Libya's anti-aircraft defences, reconnaissance capabilities and electronic warfare, as well as surveillance work during the final Tripoli battle.

Kadhafi is still at large and loyalists still in control of some towns but Libya's Western-backed National Transitional Council is already promising elections and talking about reconstruction.

With the war not yet fully won, analysts argued that the EU and NATO already had some rebuilding of their own to do in the aftermath of an operation launched without clear support from all member states.

"More than half of the 28 NATO member states were against this war," Heisbourg said.

In the Atlantic alliance, Germany was staunchly opposed to the intervention and other countries such as Poland refused to contribute despite repeated calls while Turkey only agreed to a minimal role.

"There is an obvious political weakening of NATO," Heisbourg said.

"From March 31, NATO played host to the operational command centre but it never controlled policy and strategy," he added.

Another collateral victim of French-British leadership was the ever-recurring issue of a joint European Defence project.

"Europe as a political and strategic force was completely absent, that is the sad truth," said a European diplomat.

In the longer term, analysts voiced doubt that a split NATO leadership, with the Europeans taking the lead on wars closer to their patch and the US on faraway operations, was sustainable.

Heisbourg argued that Washington's shrinking defence budget was one of the reasons for its limited involvement in Libya.

That leaves Europeans less available for other theatres such as Afghanistan and will also force them to invest in certain types of equipment for which they usually relied on Washington.

"We have a structural problem because European states also have economic problems, don't have much spending power and tend to turn to the United States," Dumoulin said.