A jammed Glock and two extended ammo magazines were later recovered at the scene — suggesting the gunman could have unleashed more mayhem if his weapon hadn’t malfunctioned, law-enforcement sources told The Post.

The gunman — who is still in the wind — was wearing a “green construction-type vest” and gas mask when he launched his bloody assault aboard a Manhattan-bound N train around 8:24 a.m. just as the subway was pulling into the 36th Street station in Sunset Park, NYPD Commissioner Keechant Sewell said during a news briefing at the scene.

“An individual on that train donned what appeared to be a gas mask. He then took a canister out of his bag and opened it,” Sewell said. “The train at that time began to fill with smoke. He then opened fire, striking multiple people on the subway and on the platform.”

The commish said the incident wasn’t being investigated as an act of terror at the moment and noted none of the victims were of a particular ethnic group, but she also added that no motive has been ruled out.

The suspect shot 10 people, including five who are in critical but stable condition, the FDNY said. Some of the victims suffered smoke inhalation, but none of those injured has life-threatening injuries, Sewell said. A pregnant woman was among those hospitalized, sources said.

A slew of injured victims walked into hospitals themselves for treatment, officials said.

The suspect, described as a black male, approximately 5 feet 5 inches with a heavy build, is still on the loose.

Police later recovered the jammed gun with extended ammo, a hatchet, a can of pepper spray, two gas canisters, a bag full of fireworks and another satchel holding what appears to be BB pellets at the scene, sources said.

Detectives believe that at least the gun belonged to the suspect, sources said.

“It was lucky that it jammed because we could be talking about a lot more people in hospitals or worse,’’ a law-enforcement source said. “Dozens more people would have been wounded or more seriously injured.’’

It was not immediately unclear which of the other items may have been the gunman’s also, sources said.

The FDNY said earlier Tuesday that several undetonated devices were found at the 36th Street station. The NYPD later said, “There are no active explosive devices at this time.”

As the mayhem unfolded, straphangers were evacuated to the R train across the platform, where some got off at the next stop and others were rushed to hospitals.

“They just started yelling,” said Gaba Semein, 16, who was at the 36th Street station en route to class when the mayhem unfolded, referring to people around her.

“They told us to switch to the R. Everyone got on, including a guy who got shot. He hobbled on,” he said.

Footage taken from the chaotic scene showed screaming passengers spewing out onto the platform as soon as the train doors opened and clouds of smoke billowing out.

Graphic photos on social media showed the injured lying on bloodstained subway platform floors.

A straphanger who was on the train when the violence broke out told The Post there were so many rounds fired off, she “lost count.”

“There was like, lots of them. I don’t even know how many,” said the woman, who only gave her first name, Claire.

She said she saw the suspect drop “some kind of cylinder that sparked at the top.

“I thought he was an MTA worker at first,” she said.

The NYPD’s bomb squad was on the scene investigating, and authorities were scouring MTA surveillance to try to identify the suspect, but sources told The Post cameras on the station’s platform and turnstiles hadn’t been working since Friday.

While the suspect was already on the train after having entered at another location, the surveillance footage could have caught him leaving after the attack.

Cops asked reporters at the scene to be clearly identified so the suspect would be less successful in any attempt to blend in with the crowd.

The injured were taken to a number of area hospitals, including NYU Langone of Brooklyn, Kings County Hospital, Methodist Hospital and Maimonides Hospital, which had five victims with non-life-threatening injuries, a rep confirmed.

During the news briefing, a visibly angry Gov. Kathy Hochul decried the bloodshed.

“We say no more — no more mass shootings, no more disrupting lives, no more creating heartbreak for people just trying to live their lives as normal New Yorkers. It has to end, and it ends now,” Hochul said.

“We are sick and tired of reading headlines about crime, whether mass shootings or the loss of a teenage girl or a 13-year-old. It has to stop,” she continued, adding she is “committing the full resources” of the state to cut down on crime.

Mayor Eric Adams, who is currently isolated with COVID-19, has been briefed on the incident and has made all of the city’s resources available as the investigation continues, a spokesman said.

“While we gather more information, we ask New Yorkers to stay away from this area for their safety and so that first responders can help those in need and investigate,” the spokesman said.

Schools in the immediate vicinity are sheltering in place, city Education Chancellor David Banks said in a statement.

“Following the incident this morning in Sunset Park, out of an abundance of caution and for the safety of our students we have placed all schools in the area in a shelter-in-place. We are working closely with NYPD and school leadership to ensure that every school has the supports they need as we work to ensure the safety of our school communities,” Banks said.