Paris ? European neo-Nazis post online pictures of paint-smeared mosques. Web sites of Islamic radicals call for holy war on the West. Aliases like “Jew Killer” pop up on Internet game sites.

International experts met Wednesday in Paris to tackle the tricky task of fighting anti-Semitic, racist and xenophobic propaganda on the Internet, seen as a chief factor in a rise in hate crime.

Purveyors of hate have found a potent tool in the Internet, spreading fear with such grisly images as the beheading of Wall Street Journal reporter Daniel Pearl in 2002.

The new technology has proven to be a boon for hatreds of old, many experts say.

“Our responsibility is to underline that by its own characteristics — notably, immediacy and anonymity — the Internet has seduced the networks of intolerance,” French Foreign Minister Michel Barnier said in opening remarks at the two-day conference.

France, which is spearheading the effort, has faced a surge in anti-Semitic violence in the last two years. Some fault the growth of Internet use among hate groups.

But differing views about the limits of free speech and the ease of public access to the nebulous, anonymous Web largely stymied officials hoping to find common ground in Wednesday’s talks.

A sticking point was whether the United States, which has championed nearly unfettered free speech, would line up with European countries that have banned racist or anti-Semitic speech in public.

The dilemma is all the more acute because the Internet is global, easy to use and tough to regulate — as shown by widespread sharing of music online, an illegal practice that has confounded record companies. Terror groups have also used the Internet to plot attacks.

The Organization for Security and Cooperation in Europe, a 55-country body that promotes security and human rights, organized the conference with the backing of the French government. Six countries in the Middle East and North Africa also sent envoys. The meeting is one of three OSCE conferences on anti-Semitism and racism this year.