A man has been “unintentionally” shot by police after officers responded to reports of a woman being held against her will by armed men at a south London pub.

Police received a call at 3.55am on Saturday from a woman who said that another woman was being held against her will at the Anchor pub in Lewisham.

Armed officers responded and stopped a car being driven from the pub during which a police firearm was “unintentionally discharged” close to Blackheath Hill and a man sustained a gunshot injury.

The victim – believed to be in his 20s – was taken to a hospital in south London but his condition is not considered life-threatening. The man has been arrested along with another occupant from the vehicle.

The Independent Office for Police Conduct has launched an independent investigation into the shooting and the directorate of professional standards has been notified.

Officers attended the Anchor pub and arrested five other men, yet no woman was found during a search of the pub.

Detectives have appealed for witnesses but are not confirming further details about police searches or items found, including firearms.

The reports of a woman being held against her will are being investigated by detectives from the south-east criminal investigation department, who want the original caller – who only gave her first name and who called from a phone box on Morden Hill, just off Lewisham Road – to make contact.

Det Ch Insp James Stanyer said: “Detectives are working hard to fully understand this incident and our inquiries are at an early stage.

“It is vital that we hear again from the original caller in this case. Officers, including armed police, rightly deployed urgently to the area following her phone call, and this has resulted in a number of searches and seven people being arrested.

“Whatever the circumstances of the call, it is important that this [woman] calls police again as soon as possible.”