At least six people have been injured, three of them critically, in a stabbing on board a bus in the western German city of Siegen, police said on Friday evening.
A 32-year-old female suspect has been arrested, police said.
Another person suffered serious injuries, it said.
At least 40 people were on the bus travelling to a city festival in Siegen, located some 75km (45 miles) east of Cologne, when the attack occurred at around 7.40pm, according to the police statement.
Several passengers alerted the police and officers arrested the suspect, a German national.
The motive of the crime remained initially unclear. Police said there was no indication of a terrorist attack.
Germany’s Bild tabloid reported that the attacker may have been suffering from mental health issues.
The incident comes exactly one week after the fatal stabbing in the western German city of Solingen, where a knife-wielding attacker killed three people and injured eight.
The suspected perpetrator, a 26-year-old Syrian citizen, is in custody.
The Islamic State terrorist group has claimed responsibility for the crime, although German authorities are still investigating the credibility of the claim.
Police in Siegen appealed to citizens “not to spread false reports on social networks or other channels, and in particular not to make any reference to a terrorist attack”.
There was no information suggesting such a motive, they added.
Police were still on site on Friday evening. The crime scene has been cordoned off, evidence is being secured and witnesses are being questioned, according to the statement.
The bus was part of a special service to allow more people to travel to the festival marking the city’s 800th birthday this weekend.
Organisers expressed concern about security after the attack in Solingen. The existing security concept and operational planning had been scrutinised once again, Siegen Mayor Steffen Mues was quoted as saying on the city festival website.
“Not cancelling the city festival is also a sign of democracy and freedom,” he said.
Visitors to the city festival are not allowed to carry knives, according to the city’s website.
