German police investigating four people suspected of planning an Islamist-motivated attack raided nine locations in Berlin and the eastern state of Saxony Anhalt on Thursday, prosecutors said.
The four suspects, aged between 18 and 21, are accused of being members of the Islamic State group, prosecutors and police said in a statement.
Three are believed to be in Syria: two traveled from Berlin via Istanbul to Islamic State-held territory in Syria in November 2016 and a third is accused of receiving military training in Syria. The fourth is believed to have helped the other three travel there.
Prosecutors did not say if any arrests were made in the raids, mounted by some 130 officers, including special forces, who confiscated electronic devices.