There are more than 6,300 Salafists currently active in Germany, whereas three years ago the number was just 3,800, according to domestic intelligence chief Hans-Georg Maassen.

"It's a very rapid rise and it's very alarming," Maassen told Radio-Berlin-Brandenburg (rbb-Inforadio) in an interview on Saturday. The number of Salafists in Germany could rise to 7,000 by the end of the year, he said.

Salafism, the most widespread form of Islamist extremism in Germany, calls for a return to the way Muslims lived during the Prophet Mohammed's era.

Disaffected youth

The recruits are normally men between the ages of 18 and 30, according to Maassen. They often come from families with migrant backgrounds and have struggled with social adjustment. Maassen said that Salafist groups provide a sense of belonging and direction to wayward youth, "giving the impression that they will go from being underdogs to top dogs."

At least 450 people have left Germany to fight with Islamist groups in Iraq and Syria, according to authorities. There's been growing concern in Berlin that some jihadists could return from the battlefield and carry out terrorist attacks in Germany. Around 150 have returned to Germany so far, with at least 25 of them having participated in fighting.

"These are people that we can name," Maassen said. "Our problem is that there are constantly people popping up in Iraq and Syria that we haven't heard of before."

Prevention key

The German government has barred its citizens and legal residents from joining the fight in Iraq and Syria under threat of prosecution. There has also been talk of withholding the passports of people that German authorities believe are at risk of going to Iraq and Syria.

But Maassen said that authorities should emphasize prevention over changes to the law, by making sure that "recruiters - who show up at town squares and schools and distribute Korans - don't have access to young people."

slk/se (AP, dpa, Reuters)