Prime Minister Francois Fillon will ask for a parliamentary vote of confidence in France's plan to rejoin the military command structure of NATO, his office said on Thursday.

President Nicolas Sarkozy is expected to announce France's full return to the command structure, which it left in 1966 in protest against what it saw as U.S. hegemony in Europe, at a NATO summit in Strasbourg in April.

But he has faced mounting resistance from opposition parties as well as members of his own UMP party, with critics arguing France will lose its ability to act as a counterweight to the United States and forge independent diplomatic alliances.

"At the next council of ministers, I will ask the president to authorise a vote of confidence before parliament," Fillon wrote in a letter to members of the opposition.

The NATO move does not require ratification by parliament, but the vote will have a symbolic force.

Many security experts see France's return to the command structure as a mere formality, given that it is already one of the most active members of the North Atlantic alliance.

French troops are fighting in NATO missions from the Balkans to Afghanistan, where there are some 2,800.

Sarkozy has said that returning to the fold will give Europe greater weight within U.S.-dominated NATO. European arms manufacturers also hope that such a new balance will boost their business, which faces tough competition from U.S. companies.