A burning car was rammed into a synagogue door in southwest France as the interior minister convened Muslims, Jews and police in Paris to warn against contagion from the Gaza conflict.

Damage to the synagogue in a Toulouse neighborhood was limited to a blackened door, and there were no injuries even though a rabbi was giving a course to adults inside, said an official of the regional prefecture, Anne-Gaelle Baudouin.

Police called to the scene found remnants of a Molotov cocktail in the car and a car nearby with three unlighted Molotov cocktails, Baudouin said.

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It was not clear whether the incident Monday night was in any way a reflection of frustrations in France as Mideast tensions rise. France has western Europe's largest Muslim and Jewish communities.

Nevertheless Interior Minister Michele Alliot-Marie said she was concerned about the prospect of contagion. She held a meeting late Monday with the heads of the two main Muslim and Jewish groups and police officials to stress the need to "preserve national unity" so that the conflict between Israel and Hamas, the militant Palestinian group ruling Gaza, did not feed passions in France.

Anti-Semitic and anti-Muslim incidents in France have risen in the past when Mideast tensions mounted significantly. In 2002, some 2,300 Jews left France for Israel because they felt unsafe. Incidents of Islamophobia also have been reported.

Alliot-Marie asked the French Council for the Muslim Faith and the Representative Council of Jewish Institutions of France, or CRIF, for "special vigilance" given the "tense international context," a ministry statement said.

At least 21,000 people protesting the Israeli offensive in Gaza marched through Paris on Saturday, shouting "We are all Palestinians" and "Israel assassin." A group of some 500 later turned violent, burning Israeli flags, torching cars and vandalizing several shops, police said.

A group calling itself the National Bureau of Vigilance Against Anti-Semitism said in a statement that all such gatherings should be banned because they "incite violence, hate and put the ... Jewish community in danger."

President Nicolas Sarkozy, meanwhile, was on a two-day mission to the Middle East hoping to encourage a temporary cease-fire between Israel and the Hamas organization ruling Gaza.