A police officer and at least four other people were shot and killed, and several others injured, by a crazed gunman who stormed a swanky Midtown skyscraper early Monday evening — before turning the gun on himself, sources said.

The 27-year-old maniac, identified by sources as Shane Tamura, barged into the 44-story building — which houses Blackstone and the NFL headquarters — armed with a rifle and opened fire at around 6:30 p.m. during the evening rush, law enforcement sources told The Post.

The suspected shooter is seen entering the Manhattan building with a rifle.

Footage posted to social media shows bystanders running for their lives outside the building and workers were also later seen filing out of the high-rise with their hands up.

A witness on the first floor said that “it sounded like a barrage of shots …Like an automatic weapon. Like a high-capacity weapon.”

“I was at work and this guy came in with an assault rifle and started shooting,” a man, who was gasping for air outside 345 Park Avenue, told The Post shortly after the bullets started flying.

Chilling images showed the gunman, who’s from Las Vegas, calmly strolling across the Park Avenue building’s entry plaza with an assault rifle at his side before carrying out the carnage.

Sources told The Post the number of victims are expected to rise and authorities search the high-rise in the aftermath of the mayhem.

At least one police officer at the scene was shot in the back and died at a hospital. Four civilians were also gunned down and several others were injured, sources said.

After opening fire, Tamura barricaded himself inside the skyscraper and was discovered dead from a self-inflicted gunshot wound on the 33rd floor, where other victims were found, sources said.

Tamura was seen splayed out on the ground, apparently already dead, in another photo obtained by The Post.

It wasn’t immediately clear what company the 33rd floor houses.

Tamura is believed to have acted alone, NYPD Commissioner Jessica Tisch said.

“The scene has been contained and the lone shooter has been neutralized,” she wrote on X just over an hour after the chaos started.

Police recovered Tamura’s rifle, a Palmetto State Armory AR-15 assault rifle, which was smeared with blood.

A vehicle with Nevada plates registered to Tamura was found at the scene, sources said.

Tamura had a concealed firearms permit from Las Vegas with a 2027 expiration date, according to a picture of the license obtained by The Post.

Photos posted to X show who is purported to be frantic Blackstone employees stacking couches and other furniture in front of an office entrance during Tamura’s rampage.

One man person who apparently works in the Park Avenue tower was seen sitting on a marble stoop outside a nearby building hyperventilating with a bandage around their hand hours after the first shots rang out.

“I was at work and this guy came in with an assault rifle and started shooting. I was in the lobby at work,” the man said into a phone while calling a loved-one.

Oleksandr Stupak, 30, was standing on the street nearby when he heard gunshots ring out — and watched in shock as armed police flooded the building

“I was on the one block away and I heard shots being fired and then a bunch of police, they came to neutralize it,” he said. “I went to the Citizen app and it says active shooting. A lot of police started to come. I mean. [It’s ] crazy.”

The blocks surrounding the building were flooded with police cars, fire engines, ambulances and first responders, while helicopters filled the sky overhead.

And footage from the scene showed officers hastily performing CPR on an apparent victim after hauling his limp body in the middle of the street.

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The officer who was killed was from the 47th Precinct.

William C Lopez/New York Post

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Two protesters were arrested after yelling ‘Free Palestine’ around the time of the shooting

William C Lopez/New York Post

The FBI and bomb squad has also responded to the scene.

Mayor Adams has been briefed on the incident, and cautioned New Yorkers to avoid the area.

The 36-year-old slain officer was from the 47 Precinct, but was working a paid detail for the owner of the building, Rudin Properties, at the time of the shooting, sources said.

He’s been on the force since December 2021 and leaves behind a wife, who is eighth months pregnant, according to a high ranking police source.Meanwhile, two apparent protesters, including one who yelled, “Free Palestine, I’m not the shooter,” were arrested outside of the building around the time of the shooting.