German Islamists Pierre Vogel (R), Sven Lau
German Islamists Pierre Vogel (R), Sven LauReuters

German police Tuesday arrested one of the country's most prominent Islamist preachers on charges of supporting a "terrorist group" fighting in Syria.

The man, German citizen Sven Lau, 35, made headlines last year by organizing a vigilante "Sharia Police" group that patrolled German streets seeking to enforce Islamic law.

Lau is accused of supporting and recruiting fighters for the Syria-based Jaish al-Muhajireen wal-Ansar (JMA), or Army of Emigrants and Supporters, which Germany lists as a terrorist organization.

Prosecutors said that in 2013, Lau was the JMA's main contact in Germany, based in the western city of Duesseldorf, and recruited two volunteers.

They also accused Lau of delivering 250 euros ($275) in cash to a German fighter in Syria, and of organizing the delivery of night-vision equipment worth 1,440 euros to the JMA.

The JMA, with fighters from Chechnya and central Asia, in September this year pledged allegiance to the Al Qaeda affiliated Nusra Front, but a breakaway group earlier joined the rival Islamic State (ISIS).

The prosecutors charged that the JMA wing Lau belonged to backed ISIS, a group that had committed war crimes including "mass executions, the burning of prisoners, and...beheadings."

Lau was arrested in the state of North Rhine-Westphalia, a hotspot for fundamentalist Islam from where several German "foreign fighters" in Syria and Iraq come.

Lau gained notoriety when in 2014 he led young Muslims wearing orange vests marked "Sharia Police" through the western city of Wuppertal telling people not to drink alcohol, listen to music or gamble.

AFP contributed to this report.