New York City has seen a sharp rise in violent crime during the pandemic, including a string of seemingly random attacks on its subways in recent weeks.

Transit crimes are up 68 per cent and shooting incidents are up 8.4 per cent on last year, according to the latest numbers from the New York Police Department (NYPD).

Mr Adams, who has vowed to improve safety for commuters by increasing police patrols and expanding mental health outreach programs, called Tuesday’s incident “a senseless act of violence” and pledged to double the number of officers assigned to subway security.

It came as more details emerged on Wednesday of the shooting.

One survivor described how they sat next to the gunman as he pulled an axe and gun from his duffel bag before he threw a smoke grenade and fired 33 shots.

“When [the train] was about to hit 36th street, we stopped for five minutes. He takes out a gas mask from one of his little luggage[s],” passenger Fitim Gjeloshi told the New York Post. “He opened one of his gas tanks, and he said, ‘Oops, my bad’. He pulls out an axe, he drops it, he takes a gun out, he starts shooting.”

Neighbours of Mr James in Milwaukee described him as a “really weird neighbour” who was quiet and walked with a limp.