The 64-year-old's motive for bringing the shotgun to the world body’s complex remains unknown, according to Roskosky.
"He has been charged with criminal possession of a weapon, making a terroristic threat, menacing, reckless endangerment, obstructing governmental administration, disorderly conduct," Roskosky said.
The individual was arrested on Thursday after several hours of NYPD’s attempts to establish a dialogue with him. He came to New York from the US state of Florida and has no criminal history.
The gunman agreed to put down the weapon pointed against his neck after police handed documents, including medical papers, he had with him, over to the United Nations.
The individual was then taken to a hospital, where he remains as of Friday, Roskosky said.