Signs are mounting that the conflict in Gaza is starting to spill over into violence in Europe's towns and cities, with assaults against Jews and arson attacks on Jewish congregations in France, Sweden and Britain.

Assailants rammed a burning car into the gates of a synagogue in Toulouse, in southwest France, on Monday night. A Jewish congregation in Helsingborg, in southern Sweden, also was attacked Monday night by someone who "broke a window and threw in something that was burning," said police spokesman Leif Nilsson. Neighbors alerted rescue services before the fire took hold.

Someone also started a blaze outside the premises last week. And on Sunday slogans including "murderers ... You broke the cease-fire" and "don't subject Palestine to ethnic cleansing" were daubed on Israel's embassy in Stockholm.

In Denmark, a 27-year-old Dane born in Lebanon of Palestinian parents is alleged to have injured two young Israelis last week, opening fire with a handgun in a shooting that police suspect could be linked to the Gaza crisis.

France has Western Europe's largest Jewish and Muslim communities and a history of anti-Semitic violence flaring when tensions in the Middle East are high. In 2002, some 2,300 Jews left France for Israel because they felt unsafe.

President Nicolas Sarkozy warned in a statement Tuesday that France would not tolerate violence linked to the Gaza crisis. A day earlier, his interior minister said she was concerned about the prospect of contagion and met with the heads of the two main Muslim and Jewish groups and police officials to stress the need to "preserve national unity."

Damage to the synagogue in Toulouse was limited to a blackened gate, and there were no injuries even though a rabbi was giving a course to adults inside, authorities said. They said unlighted gasoline bombs were also found in a car nearby and in the synagogue's yard. A local Jewish leader, Armand Partouche, said he believed the assailants had planned to torch the synagogue, but fled when the building's alarm went off.

"It could have been very, very serious," Partouche said in a telephone interview. "There were people inside; there could have been deaths."

He said Jewish leaders are asking Toulouse authorities for reinforced security for the city's synagogues.

"We really fear that anti-Semitism will spring up again and that the current conflict will be transposed to our beautiful French republic," he said.

In Britain, the Community Security Trust, a Jewish defense group, said it had seen a rise in anti-Semitic incidents since the start of Israel's offensive against Gaza. The group said it had recorded 20-25 incidents across the country in the past week that it believed were connected with Gaza, including an arson attempt on a synagogue in north London on Sunday.

London police are investigating the attack, in which suspects splashed flammable liquid on the door and set it on fire.

Community Security Trust spokesman Mark Gardner said that in another incident last week a gang of 15-20 youths walked along the main street in Golders Green, a largely Jewish neighborhood in north London, shouting "Jew" and "Free Palestine" at passers-by.

"It could get worse," Gardner said. "We tend to see these things happen in waves."

The government in Belgium on Tuesday ordered police in Antwerp and Brussels to be on increased alert after recent pro-Palestinian protests ended in violence and dozens of arrests. Police said burning rags were shoved through the mailbox of a Jewish home in Antwerp last weekend. Damage was limited and no arrests were made.

In the Danish shooting, one Israeli man was shot in the arm and another in the leg as they were selling hair care products in a shopping mall. Eli Ruvio, who owns the company that operated the stands, said his employees have been harassed by Muslim youths since they set up three kiosks in the shopping center in August.

"They kept cursing and shouting at us," Ruvio told The Associated Press. He added that the Muslim youths also threw mud and firecrackers at the employees and spat at them.

Ruvio recalled an episode Dec. 27 when some of the youths shouted "slaughter all the Jews."

"I told my employees not to speak in Hebrew and lie about where they come from, they should say there were from Spain or somewhere else. If people ask you where you are from, never say you're from Israel," he said.