BERLIN: A man has caused a series of motorway accidents in Berlin injuring six people, including three seriously, in what German prosecutors Wednesday described as a suspected Islamist attack.

Police said the man had caused three accidents on a city motorway in the Tempelhof-Schoeneberg district shortly before 7:00 pm (1700 GMT) on Tuesday.

After crashing into a motorbike, he got out of his mangled vehicle and told witnesses a metal box in his car contained a "dangerous object", which police said turned out to be false.

The suspect, identified only as a 30-year-old Iraqi, had targeted motorcyclists in particular in a "quasi hunt", a spokesman for the prosecution told a press conference.

Local media reported that he had shouted "Allahu Akbar" (God is greatest) when he emerged from his black Opel Astra.

"The possibility of an Islamist attack cannot be ruled out," prosecutors said in a statement.

"Statements by the accused suggest a religious Islamist motivation" for his actions. "There are also indications of psychological instability," they added. He was arrested on suspicion of attempted murder in at least three cases and is to face a judge who will decide whether he should be placed in a psychiatric facility.