Police say a man with a knife has lightly wounded at least four people in Munich. Officers have launched a manhunt for the assailant, who fled the scene.

Munich police called on people in the Rosenheimer Platz area, located close to the German city's downtown, to stay inside after the incident on Saturday morning.

They also urged people to avoid the area around the nearby Ostbahnhof railway station and a park, because there were conflicting accounts of the direction in which the suspect fled.

Police said the man appeared to be about 40 years old and had a black bicycle, gray trousers, a green jacket and a backpack. They later updated their description to say that he has a "corpulent figure," has short blond hair and is unshaven.

The police department said on Twitter that officers are looking for the assailant "with all available police forces."

It said the motive for the attack was not immediately clear.

None of the injuries were considered life-threatening.