The popular on-line social networking site Facebook came under fire this week for hosting a number of fascist and hate-sponsoring groups. In the week commemorating the 1918 end of World War I and the 1938 pogrom against Jews known as Kristallnacht, European politicians and the Simon Wiesenthal Center blasted the site for allowing "offensive" and "shameful" groups to be formed on its network. The critics pointed to seven known Italian fascist groups that had created groups on Facebook with titles such as "Turn gypsies into fuel," "Useful work for gypsies: testers of gas chambers," and "Let's burn them all." The groups' Web sites include images of Nazi salutes. "The existence of these groups is repulsive. I call upon Facebook to remove them immediately," European Parliament Socialist Group leader Martin Schulz, a German, said in a statement. "It is shameful that on the day Europe marks the deaths of those who fell in war, Facebook is helping those who want to take us back to those dark days." Gianni Pittella, head of the Italian socialist bloc in the European Parliament, said, "This is a day of shame for Facebook." In a letter to Facebook founder Mark Zuckerberg, the Wiesenthal Center's director for international relations, Shimon Samuels, said he was outraged to discover "the networking service abused for the propagation of attacks on Roma," and urged Facebook to remove the groups and "install appropriate filters." Despite the demands, enforcement may be difficult. Launched in 2004, Facebook says it has more than 120 million active users who participate in over six million groups. The site can be accessed in 20 languages and is the fourth-most trafficked Web site in the world.