ROME — Synagogues are torched. Jewish cemeteries are desecrated. Jews are roughed up on the street.

The recent wave of anti-Semitic violence in parts of Europe has sounded alarm bells in the Jewish world, prompting some commentators to compare the situation to the early days of the Holocaust.

"Friends in Israel — Israel! — phoned to ask if we were safe," said one mother of two in Paris. "I couldn't believe it."

The upsurge of anti-Semitism has coincided with the conflict in the Middle East and sharply intensified during the past month, when Israel launched a large-scale military operation in the West Bank to round up terrorists.

But the manifestations of anti-Semitism differ from country to country, and there is ample evidence that other elements are involved, too, including a reemergence of "traditional" religious and racial prejudices against Jews.

"The prejudices are the old ones, but the phenomenon is broader," said Andras Kovacs, an expert on anti-Semitism and nationalism at Budapest's Central European University.

"Being anti-Israel has become somehow 'legitimate' today," he said. This in turn "gives a new 'legitimacy' to the old anti-Semitism."

Why this is happening, what it might portend, and to what extent the trend is linked specifically to the Middle East crisis are matters of pressing concern to individual Jews, Jewish communities and Jewish policy-makers.

Much of the new anti-Semitism has manifested itself in headline-grabbing spate of violent attacks against synagogues, Jewish institutions and individuals, primarily in France but also in other countries, including Belgium and Germany.

To date, no one has been killed in any anti-Semitic acts in Europe. But the Simon Wiesenthal Center went so far as to issue a travel advisory for Jews heading to France and Belgium.

The European Jewish Congress counted some 360 anti-Jewish incidents in France in the first three weeks of April alone.

According to France's Interior Ministry, more than 60 percent involved anti-Jewish graffiti or verbal abuse. But there also were a dozen attempts to set synagogues on fire or damage graves.

Most of the attacks were the acts of alienated young Arab immigrants hitting out at Jews as surrogates for Israel, and were not part of an orchestrated campaign.

But the anti-Semitic violence has been coupled with a subtle ideological shift.

Widespread sympathy for the Palestinians and widespread identification of Jews and Judaism with Israel and its policies have opened the door to a growing acceptance of classic anti-Semitic rhetoric in both public discourse and private conversation.

"There is a difference between what's going on in France and Belgium and what's going on in Italy," said Francesco Spagnolo Acht, director of a Jewish music study center in Milan. "In Italy, so far, there has not been any violence. Here, anti-Israel and anti-Semitic opinions are spread by local Italians. It is ideological, but very vocal."