Hamburg shooting: Screams heard as unknown gunman opens fire on police from high rise (video)

Shooters have reportedly opened fire on police officers from the sixth floor of a building in Hamburg, Germany, sparking a huge emergency services response. 

An area in the Altona area of the city has been cordoned off where heavily armed officers are at the scene. A number of screams are said to have been heard as the incident continues. 

German police were seen taking cover behind their vans in the area as a number of shooters are said to have barricaded themselves inside on the sixth floor.