"Thank you to the amazing men and women of the NYFD who extinguished a fire in a residential apartment at @TrumpTower," he tweeted. "The @FDNY and @NYPD are truly some of the most incredible people anywhere!"
The FDNY called it a mass emergency response and sent dozens of firetrucks to the 58-story skyscraper.
In videos from the scene, flames could be seen leaping out of several windows, with debris flying into the air and onto the street.
There was a minor fire just three months ago in a cooling tower on the roof of the Midtown skyscraper, in which two people suffered minor injuries.
"We had one minor injury to a firefighter, some debris fell on him," FDNY Chief Roger Sakowich said at the time. "We had one engineer that got up there with a fire extinguisher and breathed in some of the smoke, but he's refused medical."
The high-rise houses both residences and businesses.
This is a developing story.
