A French fighter jet fired Saturday on a Libyan military vehicle, the first reported offensive action in a international military operation against Libyan leader Moammar Gadhafi's forces, a French defense official said.

French Defense Ministry spokesman Thierry Burkhard says the strike happened at 1645 GMT on Saturday.

Burkhard says the target was confirmed as a military vehicle, but it was not clear what kind. He said no hostile fire on the French jet has been reported.

It was the first reported offensive military action against Gadhafi's troops, since the UN Security Council approved a resolution on Thursday, authorizing operations to protect civilians in Libya.

France sent a dozen Mirage and Rafale jets Saturday to survey the one-time opposition stronghold of Benghazi and the 150 kilometer-by-100 kilometer no-fly zone, Burkhard said.

"All aircraft that enter into this zone could be shot down," he said.

The strike came less than two hours after top officials from the United States, Europe and the Arab world agreed in Paris to launch a risky military operation to protect civilians from attacks by Gadhafi's forces.

It also came after Libyan government troops forces attacked Benghazi earlier Saturday, apparently ignoring a proclaimed cease-fire.

The United States, Britain, France and 19 other participants in an emergency summit in Paris on Saturday "agreed to put in place all the means necessary, in particular military" to make Gadhafi respect a UN Security Council resolution Thursday demanding a cease-fire, French President Nicolas Sarkozy said.