BERLIN (AP) - German authorities are investigating two men of Tunisian origin suspected of planning to use model airplanes for terrorist attacks, prosecutors said Tuesday, as police in Germany and Belgium raided a series of sites searching for evidence of "possible attack plans and preparations."
No one was arrested in Tuesday's raids, which were carried out in the Stuttgart and Munich areas of southern Germany and in Saxony in eastern Germany, federal prosecutors said in a statement. One site in Belgium was raided, German officials said without elaborating.
Prosecutors said the investigation involved possible charges of "preparation of a serious, state-threatening act of violence," but they did not mention membership in any specific terrorist organization.
The two Tunisians are suspected of "procuring information and objects to commit Islamic extremist explosive attacks with remote-controlled model airplanes," prosecutors added. They gave no further information on the two men and didn't identify them.
However, the public broadcaster in southwestern Germany, SWF, quoted unnamed sources as saying that the two were studying aeronautics in Stuttgart and were suspected of trying to develop techniques for remotely piloting model planes using GPS technology.
German authorities would not say whether the alleged plot was far advanced, but the German news agency, quoting unnamed security sources, said the suspects had been under surveillance for more than a year.
The agency said authorities had recently detected "an increased interest in explosives and model aircraft."
However, authorities added that the national terror threat had not been raised, suggesting police believe the alleged plan - if there were one - was in early stages.
Among the locations raided were the apartments of four acquaintances of the two men who were suspected of financing Islamic extremism, officials said. The investigation also targeted another acquaintance suspected of money laundering. None of the suspects was identified.
Last November, a U.S. man, Rezwan Ferdaus, was sentenced to 17 years in prison over a plot to fly remote-controlled model planes packed with explosives into the Pentagon and U.S. Capitol.
Last year, Spanish police released a video they claimed showed suspected al-Qaida members training for a bombing raid using a model plane. Two Russians of Chechen origin were charged with possession of explosives but were released in April for lack of evidence. A Turk living in Spain was also arrested but later released.
Germany has seen only one successful attack by an Islamic radical - the fatal shooting of two U.S. airmen at Frankfurt airport in 2011 by a Kosovo native who grew up in Germany and became radicalized by watching jihadist propaganda on the Internet.
However, there have been several attempted attacks in the country, which is a major contributor to international forces in Afghanistan.
Separately Tuesday, French authorities said police detained six people in the Paris region on suspicion of plotting terrorist attacks in France.