The stabbing of 10 people Friday on a bus in the northern city of Lübeck does not appear to have been politically motivated, German police said.

"The identity of the assailant is now clear. He is a 34-year-old German national who lives in Lübeck," police said on Twitter.

According to the police, the Iranian-born assailant shows no signs of "political radicalization" or having a terrorist background.

A spokeswoman for the prosecutor's office, Ulla Hingst, told a press conference that the knife attack was carried out with a 13-cm (5-in) blade and that the suspect had lived in Germany for some years.

The attack took place at around 1 pm and the prosecutor's office had repeatedly called for patience before issuing a statement, in the midst of multiple speculative accounts spread in the media.

The circulation of vehicles was reestablished in the mid afternoon, after traffic had been blocked for several hours around the scene of the incident due to a suspicious abandoned backpack, which was found not to contain any explosive material.

Eyewitnesses told N-TV television that the bus was full when the attack began and that the driver quickly opened the doors to let people escape.

Police in the area rushed to the scene and passengers had already subdued the assailant by the time they arrived, the witnesses said.