Crews responded Saturday evening to a fire at Trump Tower in New York that killed one man and injured four firefighters, city officials said.

The man, 67, whose name was not released pending notification of family, was taken to a hospital but later died of his injuries, said Officer George Tsourovakas, a New York Police Department spokesman. An investigation is under way.

Four firefighters also were injured as they battled the blaze on the 50th floor, including two who were burned. Their injuries are not life threatening, according to New York City Fire Department officials.

The fire started in a large apartment on the 50th floor, and when firefighters responded about 5:30 p.m. ET, the entire unit was engulfed, said Daniel Nigro, commissioner of the New York City Fire Department.

“Members pushed in heroically. They were knocking down the fire and found one occupant of the apartment,” he said, adding crews had a hard time battling the fire because it was up 50 stories and in a large unit.

Before moving to the White House, the tower that President Trump developed was his main home. He and his family own an apartment, which Forbes estimated as being more than 10,000 square feet and spans three floors.

Trump’s penthouse is on floors labeled 66 through 68, meaning the fire occurred more than 10 levels below Trump’s home. The tower really has 58 floors.

While in the building, crews checked on Trump’s home, which was unharmed, Nigro said. Smoke had spread throughout much of the building but it was unclear if any seeped into Trump’s penthouse.

No members of the first family were in the building during the incident, he said.

Onlookers outside Trump Tower took photos and video of the blaze as it grew, flames and smoke billowing from several high-rise windows. Some footage showed debris falling hundreds of feet to the street.

The president tweeted about the blaze, commending the firefighters who responded. He said the fire had been extinguished but fire officials remained at the scene for several hours due to the heavy smoke.

“Fire at Trump Tower is out,” he wrote. “Very confined (well built building). Firemen (and women) did a great job. THANK YOU!”

Eric Trump, one of the president’s sons who also helps head The Trump Organization with headquarters in the tower, tweeted out his thanks to firefighters who tamed the fire.

“Thank you to the amazing men and women of the NYFD who extinguished a fire in a residential apartment at @TrumpTower,” Eric Trump posted on Twitter. “The @FDNY and @NYPD are truly some of the most incredible people anywhere!”

In January, another fire at Trump Tower injured three people, two civilians and a firefighter. It started in the building’s rooftop heating and air conditioning system and left smoke billowing from the roof.