A man opened fire in a New York high-rise building on Monday evening, killing no fewer than four people before taking his own life, authorities said.

Among the dead was a 36-year-old New York Police Department officer, Mayor Eric Adams told a news conference, describing the incident as a senseless act of gun violence.

According to Mr Adams, another victim remains in critical condition.

The suspect, a 27-year-old man from Las Vegas with a history of mental illness, entered the building in Manhattan armed with an assault rifle and opened fire immediately.

This is according to NYPD commissioner Jessica Tisch.

He shot the police officer in the lobby, a woman hiding behind a pillar, and a security guard.

A woman exiting an elevator was spared as the shooter proceeded to the 33rd floor, where real estate firm Rudin Management is located and where he killed another person before shooting himself.

The high-rise houses offices of investment firm Blackstone and the National Football League, though the motive and choice of location remain unclear.

The suspect’s vehicle, registered in Nevada, contained multiple weapons and ammunition.

Investigators said he travelled cross-country in the days before the attack.

Authorities believe the shooting was carried out by a lone gunman.

(dpa/NAN)