A security guard was killed in Manhattan Saturday morning when a large glass panel crashed on top of him, according to officials and witnesses.

Construction workers were moving the panel on the first-floor loading area of a construction site on West 57th Street near Broadway around 10:30 a.m., when it fell and struck the guard, Harry Ramnauth, according to police.

Ramnauth, 67, was pronounced dead at the scene. A 27-year-old construction worker who was injured while trying to save him was taken to Mount Sinai St. Luke’s with non-life-threatening injuries.

“When we arrived here, [construction workers] were in the midst of getting him out,” said Deputy Chief Tom Currao of FDNY Division 3.

“[It was] a 10-by-20, very, very large glass panel that had fallen and injured — a very serious injury to the [guard],” he said.

A construction worker on the scene claimed that an entire crate of panels fell on Ramnauth.

“I don’t think he ever saw it coming,” the worker said, adding that the wooden crate held several glass panels, each weighing several hundred pounds.