Police are investigating the death of a man after he was found with gunshot wounds in south-east London.

Officers were called to Sydenham Road in the borough of Lewisham to reports of suspicious activity after 3.40pm on Sunday. Shots were heard soon after and armed police and the London ambulance service were called to the scene.

A man in his 20s died at the scene at 3.50pm despite the efforts of paramedics. Police cars were afterwards seen parked outside a Lloyds Bank branch, which was surrounded by a cordon.

“Police remain at the scene. There have been no arrests at this stage and enquiries in to the circumstances continue,” the Metropolitan police said.

Police in Lewisham said a section 60 authorisation had been made across a number of areas in the borough until 7am on Monday. It allows officers to search anyone in a designated area without suspicion for a defined period if an incident involving serious violence has taken place and “a dangerous instrument or offensive weapon used in the incident is being carried in the locality”.

Residents reacted with surprise to the incident, saying it was a safe area that had been largely unaffected by rising levels of violence elsewhere in London. Several told PA Media that they had heard reports the man accidentally shot himself. Forensic teams could be seen photographing the scene in nearby Venner Road, where the body was still lying three hours later.

A 56-year-old woman living on Venner Road said: “He came to shoot someone else, but he ended up shooting himself.

“The bullet bounced off a car window. You can see on the car window where the bullet bounced off it. After it happened, the boy he came to shoot stood there filming him.”

She said she had been stuck inside the police cordon for three hours since the shooting. “He’s been there for three hours covered by a sheet. No mum, no dad. It’s really sad,” she said.

One man, who did not want to be named, said: “We’ve heard three or four different stories – we’ve heard it was a guy on a moped, someone in a car and then that the [victim] did it to himself.”

A shopkeeper on the high street told PA that he and his colleague had also heard the victim accidentally shot himself.

“A group of guys were sitting in a car by the [Lloyds] bank and a big guy came up to them with a shotgun. They all got out of the car and ran so the guy decided to damage the car with the back of the gun.

“As he was hitting the windows, the gun went off and he shot himself – that’s what we’ve been told.”

Part of Sydenham Road, which is a high street, was closed in both directions and buses were diverted.

The death follows a number of fatal gun attacks in the capital this year, while 15 people were killed in shootings in London over 2018 – the highest yearly toll for a decade.