Units specializing in particularly serious accidents, so-called HART teams, have also been called in.
The incident is said to have taken place in the Keyham area.
The exact number of dead and injured is not yet known.
According to information to Sky News, a suspected shooter has also been killed.
A witness tells the newspaper that she saw how an armed man kicked in the door of a house and then started firing.
He then went down the street and continued to shoot at passers-by, according to the witness.
Local politician Johnny Mercer describes the incident as "serious and tragic" on Twitter.
The text is updated