New York City police responded on Monday evening to reports of an armed suspect on Park Avenue in Manhattan who shot and killed at least four people. The gunman later died from a self-inflicted gunshot wound.

CNN reported that four people, including an NYPD officer, were killed in the shooting.

Video showed a man with a long rifle walking into a building on Park Avenue.

Jessica Tisch, the New York City police commissioner, confirmed that “the lone shooter has been neutralized”. New York police also said the shooter acted alone and was dead.

The New York Times said law enforcement officials identified the shooter as 27-year-old Shane Devon Tamura of Las Vegas.

The city’s FBI field office said in a social media post it was providing support to an “active crime scene”. Officials were warning those in the vicinity to shelter in place.

Police warned people to avoid the area in a social media post shortly before 7pm ET.

Eric Adams, the New York mayor confirmed the active shooter and urged precaution.

“New Yorkers: there is an active shooter investigation taking place in midtown right now,” Adams wrote in a post. “Please take proper safety precautions if you are in vicinity and do not go outside if you are near Park Avenue and East 51st Street.”

The suspect exchanged fire with an NYPD officer in the building’s lobby at about 6.40pm ET, a law enforcement official told CNN, before moving to the 33rd floor. The same law enforcement official said the gunman was found dead in a stairwell with an apparent self-inflicted gunshot wound and a rifle.

Photographs show people exiting the building around 7pm ET with hands raised.

In a social media post, US attorney general Pam Bondi said that the US attorney for the southern district of New York has “set up a command post”, and that “local FBI agents are on the scene.”

US House minority leader Hakeem Jeffries expressed his concern over the “horrific shooting”, and said he was “praying hard” for the NYPD officer.

“May God watch over our city during this challenging moment,” Jeffries wrote in a post.

The office building at 345 Park Avenue occupies an entire city block and houses the corporate offices for the National Football League and the headquarters of investment firm Blackstone. It also holds offices for JP Morgan Chase.

According to an ESPN reporter, Jeff Darlington, an NFL security alert was sent to employees: “Do not exit the building. Secure your location and hide until law enforcement clears your floor. Please switch phones to silent.”

This shooting is the 254th mass shooting in the US this year, according to the Gun Violence Archive, a nonprofit that tracks gun-related violence, who defines a mass shooting as an incident in which four or more people, excluding the shooter, are killed or injured by firearms.