ANKARA, Turkey — French Foreign Minister Alain Juppe on Friday called on the U.N. Security Council to act against Syrian President Bashar Assad's regime, saying the time has come to strengthen sanctions against Syria over its brutal crackdown on civilians. "We must continue to exert pressure, the U.N. must act, it is not normal for the U.N. Security Council not to act," Juppe told a joint news conference with Turkish Foreign Minister Ahmet Davutoglu in Ankara. "We have called on Assad to change but the regime did not want to know, which is not acceptable. We are ready to strengthen the sanctions." Juppe said France wants to work with the Arab League and Turkey as well as the Syrian opposition. Davutoglu, responding to a question on whether his country would support a no-fly zone over Syria, said there might be need to enforce some measures if Syria maintains its crackdown on civilians. Syrian President Bashar Assad's brutal crackdown on the Syrian uprising has left an estimated 3,500 dead. Juppe urged the Syrian opposition to avoid an "armed insurrection," amid reports of armed clashes between the sides.