Many Jews in Europe say anti-Semitism is increasing, particularly on the internet, according to a survey by the EU's Fundamental Rights Agency (FRA).
The survey of 5,847 Jewish people said 66% of those who responded considered anti-Semitism to be a problem.
Three out of four respondents, 76%, believed anti-Semitism had increased over the past five years.
The survey was carried out in 2012 in eight countries which are home to about 90% of the EU's Jewish population.
Respondents in Belgium, France, Germany, Hungary, Italy, Latvia, Sweden and the United Kingdom were asked to give "their opinions and perceptions on anti-Semitic trends and anti-Semitism as a problem in everyday".
They were also asked about their personal experiences and worries about their own safety and that of family members.
There was particular concern about anti-Semitism online. About three-quarters of respondents considered that to be a problem which is getting worse.
A British woman in her 50s, quoted in the survey, said she had "experienced more anti-Semitic comments" since going on Facebook "than I ever have done throughout my whole life".
She added: "This is very dispiriting. The speed at which hostile comments and misinformation can be passed around is frightening and leads to a sense of deep unease, which may not connect with the day-to-day reality of being Jewish in a diverse society."
The survey found 29% of those surveyed had considered emigrating because of concerns about safety, with particularly high figures recorded in Hungary (48%), France (46%) and Belgium (40%).
It found one in five respondents had personally experienced at least one anti-Semitic verbal insult and/or a physical attack in the year before the survey.
Perpetrators of the most serious incidents were described as "being perceived as someone with Muslim extremist views, 27%, left-wing political views, 22%, or with right-wing views, 19%".
Respondents said the most frequent comments made by non-Jewish people in the UK were: "Israelis behave 'like Nazis' towards the Palestinians" and "Jews exploit Holocaust victimhood for their own purposes" (both 35%).
The survey showed significant differences between Western and Eastern European countries.
In Latvia, only 8% said the Israeli-Arab conflict had had a large impact on how safe they felt, but the figure rose to 28% for Germany and was as high as 73% in France.
FRA Director Morten Kjaerum said this reflected differing histories, as well as recent patterns of immigration.
"I think that there is across Europe... a traditional form of anti-Semitism that goes back in history for a long time," he said.
"But then we also see a particular sort of anti-Semitism reported by the respondents, namely the anti-Semitism which comes out of the conflict in the Middle East. And this is where you have to be careful: when do you have a legitimate critique of whatever your position may be in terms of that particular conflict and when would it be an anti-Semitic statement?"
The FRA said EU countries should work "urgently" to find effective ways to combat online anti-Semitism. It called on public figures to condemn anti-Semitic statements.