Authorities have identified a 27-year-old German convert to Islam as an Al Qaeda associate suspected of traveling to Afghanistan and planning to attack German targets.

The report could fuel concerns about European converts being recruited by Islamist terrorist groups for attacks.

The Federal Criminal Police Office confirmed a Spiegel Online report Sunday that it had posted notices across Afghanistan warning that the Kazakhstan-born ethnic German, identified as Jan Sch., may plan attacks on German military or civilian institutions in Afghanistan.

The German-language posters included a description of the suspect and his picture. They were put up at German military bases and civilian institutions, security check points, embassies and the international airport, according to Spiegel.

Jan Sch., who is also known as Hamza, has only recently traveled to the border region between Afghanistan and Pakistan, Spiegel reported. He left Germany in 2004 to study Arabic in Saudi Arabia. However, he was seen in his hometown of Saarbruecken several times after his departure from Germany.

According to the report, Jan Sch. allegedly is an acquaintance of Fritz Gelowicz, a member of an alleged radical Islamic terrorist cell whose plot to attack U.S. targets in Germany was foiled by authorities in 2007.

Spiegel also wrote that the criminal office warns of several other German extremists who supposedly have traveled to Afghanistan in recent months.

Jan Sch. "is said to be one of the intellectuals of the German Islamist radical scene, who is often asked for advice. This makes him a possible leader in the eyes of the terrorism investigators," Spiegel Online wrote.