Islamic State group members rarely recruit at mosques, a terrorism expert told a meeting organized by the U.N. Security Council’s Counter-Terrorism Committee Tuesday. About three-quarters of foreign fighters in the extremist organization are recruited through friends and about 20 percent through family members, said Scott Atran, co-founder of the Center for the Resolution of Intractable Conflict at Oxford University, according to Fox News.

“It is the call to glory and adventure that moves these young people to join the Islamic State,” he said. Most young people who joined ISIS were driven by a want to “become heroes,” Atran said, using another name for the group.

The group offered a “revolutionary pull,” and Atran compared it to the lure of the French Revolution, the Bolshevik Revolution in Russia and the Nazi party in Germany. "The Islamic State represents the spearhead of the most dynamic countercultural revolutionary movement since World War II, with the largest volunteer fighting force since World War II," he said.

Much attention has been paid to ISIS’ online recruitment, including how the group preys on vulnerable and disillusioned Western youth. Atran's findings are partly based on interviews with captured ISIS fighters. Thousands of foreigners are believed to be fighting alongside ISIS, including several thousand EU citizens.

Atran’s assertion that recruitment in mosques is rare appeared to back studies conducted in the past, which found that most mosques, at least in the U.S., shun extremist ideology. A 2010 study by Duke University found that numbers of radicalized Muslims in the U.S. were low and that Muslim-American communities effectively prevented radicalization. Community building was deemed helpful in reducing social isolation as a preventative measure against extremism. 

Atran said the West’s efforts to counter the group by warning prospective members of its brutality have not proved effective and that the international community must find a way to counter its rebellious lure.

His assertions come as a debate has raged over the relation between Western Muslims and extremism. Republican front-runner Donald Trump claimed to have seen thousands of Muslims celebrating 9/11 in Jersey City, New Jersey, following the deadly attacks in 2001. The claims were widely criticized as factually inaccurate and bigoted, and Trump has yet to provide proof for the claim. Trump has also said U.S. officials should closely watch mosques.