A bus carrying passengers in the German city of Lübeck was the scene of an apparent mass stabbing Friday afternoon, leaving several injured.

Less than ten individuals are reported to have been injured in the incident, and two of those seriously, which saw an unidentified individual drop a smoking rucksack — later found to contain some form of accelerant but not explosives — on the bus and draw a kitchen knife before attacking passengers. Some of those injured were stabbed, some punched, and others fell in the scramble to get off the vehicle after the rampage began.

Earlier reports from Germany stated that up to 14 had been injured, but this was subsequently revised down.

German newspaper Merkur reports the driver immediately stopped the vehicle and opened the doors, allowing passengers to flee the attacker. While some ran, others retaliated against the kinifeman, managing to restain him and allowing police to make their arrest. The driver was among those attacked by the assailant.

In #lübeck #kücknitz kommt es aktuell zu einem größeren #Polizei|einsatz. Wir prüfen die Hintergründe und informieren hier in Kürze weiter. — Polizei SH (@SH_Polizei) July 20, 2018

A police spokesman confirmed there had been no fatalities, said the motive was unknown but said they couldn’t rule out any motive, including terrorism. An arrest has been made of a 34-year-old German citizen with a “possible migration background” who may have been born abroad, according to media reports.

The local police force’s Twitter stated Friday lunchtime there was a major operation underway but gave no further details.

This story is developing