UNITED NATIONS (AP) _ With about 100 French peacekeepers detained in Bosnia, French President Jacques Chirac told the U.N. chief Friday he will pull his soldiers from the mission if U.N. troops are not better protected.

France, with the largest contingent of soldiers in the peacekeeping force, has repeatedly threatened in recent months to withdraw because of danger to the troops.

Chirac's remarks to Secretary-General Boutros Boutros-Ghali came as the Security Council prepared to discuss options for reforming the peacekeeping mission.

Boutros-Ghali has recommended reducing and redeploying the force, but the United States has lobbied strongly for an increased use of air power, a position that Russia opposes.

Boutros-Ghali is expected to present his recommendations next week on reforming the 22,000-member force.

Boutros-Ghali said Chirac asked for a new U.N. policy in Bosnia that would ``take in consideration the protection of the blue helmets on the ground.'' U.N. soldiers wear blue helmets.

``He mentioned that in the case that this new mandate will not be accepted, he wanted to inform me that he will withdraw the French troops from former Yugoslavia,'' Boutros-Ghali said.

The United Nations, in a show of strength, called in two NATO air strikes this week against Serb ammunition dumps. But the effort seemed to collapse after Bosnian Serb soldiers took at least three U.N. observers hostage and put some 150 peacekeepers under house arrest. Boutros-Ghali said about 100 of those detained are French.

Earlier Friday, the Security Council demanded that Bosnian Serbs free the detained U.N. soldiers.

When asked about the possibility of further bombing raids, council President Jean-Bertrand Merimee said ``it is possible that further air strikes will be decided.''

A council statement also demanded the ``immediate cessation of artillery attacks by the Bosnian Serbs against the safe areas and their population.''

Serbs bombarded five U.N.-protected areas, killing 76 people, after NATO warplanes attacked a Serb ammunition dump on Thursday.

The NATO attack was to punish Serbs for ignoring a deadline to return four heavy weapons taken from a U.N. collection point near Sarajevo.