ROME — Armed police stand guard 24 hours a day outside the main synagogues in Rome and Vienna.
Worshippers in Rome and Milan must have their bags searched before entering synagogue for High Holy Day services.
Visitors to Budapest's main synagogue, Jewish museum and communal offices have to pass through metal detectors as well as have their bags searched. Visitors to Jewish communal offices must also exchange their passports or other ID for a visitor's pass.
Last week's attack by a white supremacist on a Jewish community center in the Los Angeles area has raised concern among American Jews about security at synagogues and other Jewish institutions in the United States.
In many places in Europe and the rest of the world, however, security considerations have been well-entrenched elements of Jewish community life for decades.
"How could Americans not think of such things?" asked Annie Sacerdoti, editor of Il Bollettino, a Jewish community magazine in Milan, Italy.
Terrorist attacks by right-wing groups and individuals as well as by Arab and far-left factions dating back to the 1970s have forced many European Jewish communities to take expensive and sometimes elaborate security measures, which by now are routine.
Communities frequently install in-house measures and hire private security companies to supplement protection by local police.
In Rome and Milan, for example, cars are not allowed to park outside synagogues. Police mount an extra guard during the High Holy Days and sometimes block off the street. Worshippers have their bags searched, and private security guards stand by with walkie-talkies. Jewish communal institutions feature double security doors and, sometimes, bulletproof glass.
"I have to say that I feel uneasy sometimes at synagogues in the United States," said an American Jew in Rome. "No one checks who enters, and cars are allowed to park on the street right outside."
Rome's main synagogue was the object of a Palestinian terrorist attack in October 1982. It left a toddler dead and many injured.
That attack, which followed the Israeli invasion of Lebanon in June 1982, was part of major waves of anti-Jewish terrorism in Europe in the 1970s and early 1980s.
Most attacks were carried out by Arab or pro-Arab terrorists targeting Jewish institutions as proxies for Israel.
Among the attacks:
*In France, synagogues, schools, businesses, memorials and restaurants were hit by bombs in 1976.
*A bomb in a Paris synagogue on Simchat Torah in 1980 killed four people, and a bomb in a Jewish-owned restaurant in Berlin the same year killed a young child and injured 24.
*In 1981, a grenade and machine-gun attack on the main synagogue in Vienna and a car bomb attack on a synagogue in Antwerp left five dead and more than 100 injured.
*In August 1982, a machine-gun attack on a popular Jewish restaurant in Paris killed six people.
Attacks on Jewish sites and institutions around the world have continued through the 1990s, and the perpetrators frequently have remained anonymous.
Two attacks in Buenos Aires earlier this decade left more than 100 dead and hundreds wounded.
The synagogue in Warsaw was firebombed last year, although no one was hurt. Earlier this year, a number of Jews were killed in the bombing of a synagogue in Iraq.
This summer a bomb was defused before it went off in a Moscow synagogue.