A teenager has been arrested on suspicion of attempted murder after a two-year-old boy was shot with a handgun.

The child’s mother, who is in her late twenties, along with two men in their late teens, were also taken to hospital with gunshot wounds following the attack in north-west London on Wednesday night.

Scotland Yard arrested a 19-year-old man in early-morning raids in north London on Friday on suspicion of attempted murder.

The force said the three adult victims, who are believed to have been known to each other, were approached by a lone gunman in Energen Close, Harlesden.

He fired multiple shots at the two teenagers, hitting them, the mother and her two-year-old son, who was in a nearby car, before fleeing the scene on a motorbike.

The child is in a serious but stable condition in hospital, where his mother and the two teenagers were also taken with injuries described as not life-threatening or life-changing.

Detective Chief Inspector Rick Sewart said: “As a result of this terrible crime, an innocent two-year-old-boy is now seriously ill in hospital.

“This child was shot in a wanton act of indiscriminate violence.

“I know that people will be shocked and horrified that a little boy should be the victim of a gunman and I need the community to show their support for him, and his family, by telling police what they know.

“Anyone giving information will be fully supported and if you don’t want to give your name, you can call Crimestoppers, which is totally anonymous.

“But however you want to do it, make that call, and anyone who is doubtful should think of that little boy and his family’s anguish.”

A resident claimed the same victims have previously lost a relative in a shooting.

Describing Wednesday’s incident, the mother-of-four said: “We heard some shooting and people screaming.

“Then we saw a car drive off really fast down Taylor Lane – it was a white car but it was moving so fast I didn’t see what model it was.”

She added: “I couldn’t hear what they were saying but I heard screaming and shouting and then afterwards that white car drove off really fast.”

The Metropolitan Police were called to the scene at 9.45pm on Wednesday to reports of “shots fired”.

A 59-year-old resident said he thought he heard five gunshots minutes before officers arrived.

His 23-year-old son, a business administrator, said: “I looked out of the window but the view was blocked by other buildings.

“By the time I got downstairs, the police and ambulance were already here.

“I saw two people being taken out on stretchers.”

He said the neighbourhood had always felt quite safe, adding: “I’ve lived here for five years and never experienced anything like this.”

North West Borough Commander Roy Smith said: “This violent incident in itself is shocking but even more abhorrent is the fact that one of the victims is a young child.

“We are doing all that we can to bring these criminals to justice and I am working closely with the senior investigating officer from the Met’s Trident Command who is leading the investigation.

“The Trident team are being supported by specialist detectives from across the Met along with officers from the North West Command Unit.

“We want to hear from anyone who might have any information which could help the investigation, no matter how insignificant they feel it is.

“As a child is battling for their life, I urge everyone in the local community to support us by coming forward with any information that will help us make arrests.”

A large cordon was still in place around the scene by 4pm on Thursday, while a team of officers was combing through nearby communal recycling bins.

One resident on the adjoining street told the PA news agency: “I didn’t hear anything.”

She added: “When I woke up this morning I was really shocked when we saw all the police.”