HAMBURG, Germany (Reuters) - German-language Islamist propaganda is fuelling militancy among a small number of socially-alienated Muslim youths in Germany, say security experts, who worry that Europe's biggest economy may be a growing target for attacks.
The spread of an ultra-conservative brand of Islam and the emergence of populist preachers who oppose the integration of minority Muslims into wider society are compounding the impact of the online videos and discussion forums, they say.
Despite the prominence of Germany in the story of al Qaeda due to Hamburg's role as a base for three September 11 suicide pilots, its indigenous militant scene is much smaller than that in Britain or France and has taken longer to become active.
But security officials say it is growing, albeit on the far fringes of Muslim communities, citing a string of attacks and thwarted plots in recent years and an outflow of youths to training camps in Pakistan since 2006.
On Wednesday, a 21-year-old Kosovo Albanian confessed to shooting dead two U.S. airmen and wounding two more at Frankfurt airport in March, telling a court he was swayed by Islamist online propaganda he now realised was "lies".
The expansion of Islamist militancy in Germany reflects the growing variety of Europe's militant community, analysts say.
European converts, and Europeans of Turkish, Kurdish, central Asian and West African background are joining a movement once dominated by Britons of Pakistani ancestry or Frenchmen of north African heritage.
Across Europe, school drop-outs and ex-convicts now mix with the more educated activists who once predominated.
In Germany, militant youths increasingly read German-language Internet propaganda, an online world once dominated by Arabic, Urdu, Pashto and English, much of it expressing opposition to Germany's military presence in Afghanistan.
Populist preachers of the Salafist school of Islam, a brand of the religion that has its roots in Saudi Arabia, increasingly speak at public meetings, not just in mosques.
"They used to hide in the mosque but now they are encouraged to be public. They show their opinion," Manfred Murck, head of the Hamburg branch of Germany's domestic intelligence service, told Reuters.
"The tradition of terrorism is more or less a tradition of groups. But now we see that the group is not always necessary and that the Internet functions as a kind of virtual group."
The combined effect of the online propaganda and of preachers speaking in person to audiences "makes the whole scene of jihadists in Germany more cohesive and assertive".
Security experts point to the likes of Islamic preacher Pierre Vogel, a former professional boxer who later converted to Islam and studied in Saudi Arabia and has voiced strong objections to integrating Muslims into German society.
Another convert-turned-preacher is Denis Mamadou Cuspert, a former rapper called Deso Dogg, who now sings Muslim religious chants and believes Islam is under attack from the West. Yet another is Turkish-German cleric Mohammed Ciftci.
Experts say the expression of such views, intentionally or not, can facilitate a tolerance of violence among listeners.
"Deso Dogg is so important. He can really captivate you. These hymns can support a radicalisation process," said Guido Steinberg, an Islamic studies expert at the German Institute for International and Security Affairs think-tank.
"The jihadism scene in Germany has become a movement of the urban riff-raff. That may sound a little harsh, but it's fair in the sense that they are not accepted by society -- although they are by the Salafists."
The surge in German online propaganda seen since 2007 comes from North Waziristan, a Pakistani tribal region known for al Qaeda and Taliban activity and which remains the preferred destination for German militants seeking paramilitary training.
Many of its authors are German-speaking members of the Islamic Movement of Uzbekistan, a Central Asian jihadi movement with ties to al Qaeda and which actively recruits in Europe.
"We've seen dozens and dozens of messages from this area," said Peter Neumann, Professor of Security Studies at the War Studies Department of Kings College in London.
He said militants from Europe who prove unfit for the battlefield were put to work producing propaganda or were sent back to Europe to try to enable attacks there.
Concern over Islamists poses a delicate political test for German authorities amidst a raucous national debate about Islam and integration of Germany's 4 million Muslims, mostly of Turkish origin, in a population of 82 million.
Long considered as migrant workers who would eventually go back to their ancestral homes, these Muslims are now an established minority pushing for equal rights.
Akif Sahin, a Hamburg-based Turkish youth worker, said the radical preachers' views went against the grain of many mainstream Muslim communities who since 2005 had been working to become part of wider German society.
Salafism was growing in popularity, said Sahin, and this had to do with propagandists like Vogel.
Mainstream Muslim communities had tried to "get these extremists to quieten down because they are very aggressive about trying to extend their influence. But it's not clear whether this mainstream effort is succeeding".
Sahin said Salafis excelled at fund raising and using online social networks. Good language skills often made them better at communicating with alienated youths than imams in a large Turkish state-supported network of mosques in Germany.
Murck, Head of the Hamburg State Office for the Protection of the Constitution, said young Muslims found the new breed of outspoken activists to be "a kind of idol because they are seen as tough enough to speak out in public.
"When Vogel spoke here (in Hamburg recently) there were about 500 followers, or at least 'inquiring persons', listening. This was new for us."
Editing by Alistair Lyon