Bavaria governor says Munich car incident 'is suspected to be an ...

An incident in which a car was driven into a union demonstration in Munich on Thursday "is suspected to be an attack", Bavarian governor Markus Söder said.

The suspect is a 24-year-old asylum-seeker from Afghanistan, deputy police chief Christian Huber said.

Authorities launched a major operation near the city's central train station, a spokesperson said, according to Reuters.

The incident unfolded near downtown Munich about 10.30am (8.30pm AEDT) and a damaged Mini could be seen at the scene.

Police detained the driver and did not consider him a further threat, the force said in a post on X.

Police will investigate how far along the suspect was in his asylum application, spokesperson Thomas Schelshorn told CNN.

"What motive the perpetrator had, to drive into this crowd with a vehicle, has to be now found out," he said, adding that officers will conduct witness interviews and forensics "to get a picture at the end of what could have been behind this".

Schelshorn told CNN that some of the casualties are "seriously" injured.

"When I talk about gravely injured people, this also involves people where there's a fear if they will survive," he reflected.

The man was known to officials in connection with theft and drug offenses, the Associated Press reported, citing Bavaria's state interior minister, Joachim Herrmann.

Mayor Dieter Reiter said he was "deeply shocked" by the incident. He said that children were among those injured.

Participants in a demonstration by the service workers' union ver.di were walking along a street near downtown Munich when the car overtook a police vehicle following the gathering, accelerated and plowed into the back of the group.

Officers arrested the suspect after firing a shot at the car, Huber said.

Verdi, the key trade union for Germany's public sector, said it had no further information on the incident.

Those on the picket line were employees for local childcare services, according to the union, which organised the rally after negotiations for federal and local public service wages had stalled.

One eyewitness recalled police shooting at the car.

"I saw that a man was lying underneath the car," the eyewitness told German program BR24.

"Then I tried to open the door, but it was locked."

Eventually, the eyewitness retreated and turned to those injured, BR24 reported.

The Bavarian capital will see heavy security in the coming days as the three-day conference, an annual gathering of international foreign and security policy officials, opens tomorrow.

Bavaria's state interior minister, Joachim Herrmann, said authorities do not believe the car ramming was connected to the conference, but they still need to determine the motive.

The incident follows a series of attacks involving immigrants in recent months that have pushed migration to the forefront of the campaign for Germany's February 23 election.

Most recently, a two-year-old boy and another person were killed in a knife attack in Aschaffenburg, also in Bavaria.

- Reported with Associated Press and CNN