France has rejected the US criticism of Europe\'s performance in the NATO operation against Libyan leader Muammar Gaddafi. French President Nicolas Sarkozy has criticized the low US profile in the international campaign in Libya, saying that France and Britain are carrying most of the burden. He said they would continue the campaign until Libyan leader Muammar Gaddafi leaves. While other European leaders pushed for some kind of political solution in Libya, the French leader strongly defended the NATO-led military operation - and NATO itself. He rejected comments by US Defense Secretary Robert Gates that the alliance\'s future could be in doubt because of European reluctance to exercise military might. \"I wouldn\'t say that the bulk of the work in Libya is being done by our American friends,\" Sarkozy told reporters in Brussels at a European Union summit. \"The French and English and their allies are doing the work,\" he said. The United States has insisted on a backseat role in Libya. It led the initial coalition airstrikes in March, but in April withdrew US forces from the direct combat role, limiting them to battlefield surveillance, aerial refuelling and other support roles. Seven NATO members are now participating in air strikes: Britain, France, Belgium, Canada, Norway, Denmark and Italy. But, as Gates said, most of NATO\'s 28 members, including Germany, have refused to join the strike mission in Libya. Sarkozy would not give a timeline for an eventual end to the three-month-old air campaign, saying that would play into Gaddafi\'s hands and \"I don\'t think that would be constructive.\" \"Things are progressing. I would have liked them to progress more quickly, but they are progressing,\" he said. \"We must continue until Gaddafi leaves.\" Outgoing US Defense Secretary Robert Gates earlier this month attacked the EU nations for lacking military muscle - comments that provoked a rebuttal from French President Nicolas Sarkozy. \"It was particularly inappropriate for Mr. Gates to say that, and what is more, completely false, given what is going in Libya,\" Sarkozy told reporters in Brussels. In a June 10 valedictory speech, Gates said the Libyan campaign had exposed limitations, with an air operations center designed to handle more than 300 sorties a day struggling to launch about 150. \"I think his retirement may have led him to not examine the situation in Libya very closely because, whatever people want to say, I don\'t have the impression that the Americans are doing the bulk of the work in Libya,\" Sarkozy added. Gates is due to retire at the end of the month.