Several people have been shot dead in a shooting at a shopping centre in the German city of Munich, police say, the BBC reports.

A big operation is under way. Police are telling people to stay at home and avoid the streets.

Several people have also been injured at the shopping centre in the north-western Moosach district.

Reports speak of one or more attackers. Some shopworkers are reportedly unable to leave the building.

There is no information about a possible motive for the attack.

The security forces have been on alert after a teenage migrant stabbed and injured five people on a train in Bavaria on Monday.

The authorities had warned of the danger of further attacks.