NEW YORK (CBSNewYork/AP) – An elderly couple is dead after a fast-moving early morning fire in a luxury Manhattan high rise.

Authorities tell CBS2 that the blaze broke out at the famed River House co-op on E. 52nd Street just after 5 a.m. Saturday.

“It was a very difficult operation. They operated in high heat, zero visibility. It was a large apartment with a complex layout,” one FDNY deputy chief told CBS2’s Aundrea Cline-Thomas at the scene.

Police have identified the victims as 85-year-old Mary Merow and her husband, John. Mary was pronounced dead at the scene. John was taken to Weill Cornell Medical Center with severe burns and later died of his injuries.

Three firefighters were hospitalized with non-life-threatening injuries.

Investigators are looking into the possibility that cigarette smoking in bed may have caused the fire.

The palatial River House complex was built in 1931, with a 26-story tower and two 15-story wings. 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.

(© Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)