German authorities are investigating a series of apparently deliberate car crashes on a Berlin motorway on Tuesday evening as a potential Islamist attack, local media reported on Wednesday.

Six people were injured, three of them severely, when a man allegedly drove into several vehicles on Tuesday evening along a stretch of the German capital’s highway. The series of crashes led to a complete closure of one of the main traffic arteries of Berlin.

“According to the current knowledge, it was an Islamist-motivated attack,” a spokesman for the prosecutors’ office was quoted as saying by Focus magazine. He added that there were also indications that the 30-year-old suspect with Iraqi citizenship had psychological problems.