Cigarette smoking in bed may have been the cause of a fire that killed an elderly couple in their luxury apartment early Saturday in New York City.

The blaze ignited just after 5 a.m. at the famed River House co-op on East 52nd Street in Midtown Manhattan.

Fire officials say Mary Merow, 85, was pronounced dead at the scene, while her husband, John Merow, 89, was rushed to Weill Cornell Medical Center but died of his injuries.

GEORGIA FIRE THAT KILLED MOM, SON CAUSED BY TOSSED CIGARETTE, OFFICIALS SAY

Three firefighters were hospitalized with non-life-threatening injuries, officials said.

The fire filled the couple's ninth-floor, dozen-room apartment with smoke and sent flames out the windows. Officials say Mary Merow was found unresponsive, with severe burns.

The cause of the blaze remained under investigation.

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The River House, an Art Deco building that overlooks the FDR Drive and the East River, was built in 1931. It's been home to notable residents including Henry Kissinger, Uma Thurman and Secretary of Commerce Wilbur Ross Jr.

Current prices for apartments range from about $3 million to $14 million, according to the Street Easy real estate database.

The Associated Press contributed to this story.