CNN  — 

Police in the German town of Volkmarsen have arrested a 29-year old man, after a car plowed into a crowd of people at a parade on Monday and left at least 30 injured.

Police said that the suspect, a German citizen from Volkmarsen, was receiving medical treatment for “the injuries he suffered in connection with the incident” and would be brought before an investigating judge when his health allows.

A police spokesman said earlier that according to eyewitness accounts, the car “intentionally” rammed into the crowd of carnival celebrants at around 2.30 p.m. local time (8:30 a.m. ET).

Police and rescue workers at the scene of the incident at Volkmarsen's Rose Monday parade.

The spokesman could not confirm the driver’s motive for the incident.

The interior ministry of the federal state of Hesse said in a statement that the suspect ”drove at high speed.” It added that the man in the custody ”is currently not interrogatable.”

“Due to the situation on site, an attack currently cannot be ruled out,” the statement added.

The ministry said that a special unit had been set up in the Frankfurt Police Headquarters to investigate the incident, and that the police presence had been strengthened across Hesse.

North Hessen Police have warned against the spread of unconfirmed information. The force has asked witnesses who may have videos or photos from the scene to submit them through a special police portal, urging them not to share the images on social media.

All carnival events across Hesse were canceled on Monday after the incident in Volkmarsen. North Hessen Police said the move was a precaution.

People react at the scene after a car ploughed into a carnival parade in Volkmarsen, Germany.

Elmar Schulten, a reporter for the local newspaper Waldeckischen Landeszeitung, told CNN the incident happened near the town’s train station.

He said he “saw a silver Mercedes had broken through the police blockage” and “headed directly to the crowd.”

“I counted up to 15 people laying in the street and the walkway. Several small children laying and crying,” Schulten added. At least four or five helicopters were picking up patients from the site, he said.

Volksmarsen is a small town with roughly 6,000 residents, located near Kassel, in the north of the federal state of Hesse in central Germany.

According to Schulten, the carnival parade is a tradition in the town, with some 30 floats and 1,000 people taking part. He estimated that more than 5,000 people were watching in the streets.

Hanau, a city in southern Hesse, was the site of a deadly shooting attack by a suspected far-right extremist last week.

Police in Mainz, a city in the neighboring state of Rhineland-Palatinate, said security at the carnival event happening there on Monday had been tightened, with surveillance drones deployed.