The US and its allies suspect that Iran is trying to develop a nuclear weapon — a charge that Tehran denies. Israel views a nuclear-armed Iran as a threat to its very existence, and claiming that time is running out, has repeatedly hinted that it is prepared to strike Iran's nuclear installations if necessary.
Moshe Kantor, president of the European Jewish Congress, said he feared a minority of angry, extremist European Muslims who live in impoverished neighborhoods might use an Israeli attack as a pretext to hit local Jews, particularly in France and Great Britain.
"If Israel attacks Iran, it will be a dramatic increase of anti-Semitic, very violent attacks against Jews," Kantor said. "And the vehicle for the realization of the attacks will be these enclave communities, where the level of hatred is very high and they are prepared to attack enemies inside their countries," he said.
Israeli leaders have reacted with skepticism to the latest efforts by world powers to negotiate with Iran over its nuclear program. Israel's deputy foreign minister, Danny Ayalon, said Wednesday the talks may be an Iranian stalling tactic as it pushes forward with a weapons program. He cautioned against "falling into the trap of a good atmosphere" and urged the West to impose tougher economic sanctions on Iran immediately.
Kantor, a Russian-Swiss businessman, said his group is prodding European governments to take more measures to protect Jewish communities. He said its biggest efforts were focused on combating anti-Semitism in the radical fringes of European Muslim neighborhoods.
"We have to understand it's like a bomb ready to explode," he said.
Kantor said his group is expected to meet Israeli Prime Minister Benjamin Netanyahu on Thursday to discuss its concerns, but the chief responsibility for the safety of European Jews lay with their own governments.
He spoke at Tel Aviv University after the presentation of an annual report on worldwide anti-Semitic attacks. The report was issued before Israel's yearly memorial day for the 6 million Jewish victims of the Nazi Holocaust of World War II. The commemoration was beginning at sundown Wednesday.
The report said the number of attacks declined in 2011, but they were generally more violent than in previous years.
The report did not examine incidents in 2012, but Kantor said the deadly attack on a Jewish school in Toulouse last month highlighted his fears. A rabbi and three children were shot dead, and an extremist Muslim gunman was believed responsible.
Kantor said his organization generally expects anti-Semitic attacks to rise as European economies went into crisis, or if other violence occurred between Israel and the Palestinians.
The European Jewish Congress is an umbrella organization that says it represents some 2.5 million Jews in Europe. The largest communities are in France and Great Britain.