Around 30 people have been injured after a car was deliberately driven into a carnival parade in Germany, police said.
Officers added the driver, who they believe is a local man, has been arrested following the incident in Volkmarsen in the central state of Hesse.
Germany's Hessenschau news service said police have confirmed the motorist is a 29-year-old German citizen.
The regional broadcaster added officers were unsure of the suspect's motive.
The German tabloid Bild cited the state ministry as saying the detained driver was not fit for questioning.
German news website HNA cited witnesses as saying the driver appeared to have deliberately targeted children and had driven into the crowd "at full throttle".
Local reports suggest children are among those who have been injured.
Witnesses said the driver drove around a barrier blocking off traffic from the parade, according to the regional Frankfurter Rundschau newspaper.
The police have not received reports of any deaths and do not have a specific number of injuries.
Video footage from the scene showed a silver Mercedes station wagon with its hazard lights blinking on the pavement, while emergency workers walked nearby.
Amateur pictures published online showed police officers standing next to a silver Mercedes.
A large number of officers have been at the scene about 175 miles southwest of Berlin, and the public were being urged not to spread unconfirmed reports about the incident.
Today is Rosenmontag in Germany - Rose Monday in English - a popular day for carnival celebrations across the country.
Police said in a tweet that all carnival processions in Hesse have now been cancelled as a precaution.
It comes less than a week after a gunman shot 10 people dead in the German town of Hanau , which is also in Hesse state.
The shooting was one of the worst racist attacks in the country since World War Two.
Investigators in that incident have said that the 43-year-old suspect, who was found dead in his flat soon after the shooting, had a xenophobic motive.