he shooting sent pedestrians running for cover as police warned of an active gunman around 18:30 ET (22:30 GMT). Those inside the building cowered as gunfire echoed - some even piling couches and chairs against doors as they hid in offices.

The skyscraper is home to the National Football League (NFL), as well as financial giants like Blackstone and KPMG and other major firms.

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New York City Police Commissioner Jessica Tisch said the suspect appeared to have acted alone. She told a press conference that a fifth victim was shot and was in "critical but stable condition".

The slain police officer Didarul Islam, a Bangladeshi immigrant and father of two with a third child on the way, had served in the New York Police Department for three and a half years.

Local officials and authorities celebrated Islam, saying he died a "hero."

Tisch said: "He was doing the job that we asked him to do. He made the ultimate sacrifice."

After shooting Islam as he entered the building, Tamura then aimed at a woman who hid for cover behind a pillar. He proceeded through the lobby, "spraying" it with gunfire, hitting multiple people - including a security guard hiding behind a desk and another man nearby.