At least ten people have reportedly been killed and several others have sustained injuries in the attack.
The police sources have said at least 10 people have also sustained injuries and an investigation is also underway to ascertain if one of the assailant is among those killed.
The police forces sealed off the area around the shopping centre in the district of Moosach.
Sueddeutsche Zeitung newspaper earlier quoted police sources saying that several people have been killed but the authorities have not formally confirmed the report so far.
Eyewitnesses have said the attack has been carried out by at least three people who are on the run.
This comes as the security forces have been on alert after a migrant stabbed five people on a train in Bavaria on Monday.