The Fire Department of NY said the fire started at around 7 a.m. ET Monday at the building, which contains U.S. President Donald Trump's home and business offices.
Two people are said to have received minor injuries.
The president was not in the building when the fire erupted.
The Republican president announced his candidacy in 2015 at Trump Tower, his home for more than 30 years.
Trump's son, and the executive vice president of The Trump Organization, Eric Trump tweeted that an electrical fire in a cooling tower was being eyed as the cause.
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The Fire Department of NY said it was called there at around 7am (noon GMT) after the blaze was reported on the top floor.
Aerial views showed firefighters on the roof, with smoke billowing from one corner of the high-rise. Several other members of the Trump family also live in the tower.
At around 7 a.m., about 70 firefighters rushed to the apex of the Fifth Avenue Trump Tower skyscraper at 57th Street in midtown Manhattan to put out the blaze, fire officials said.
Trump was in Washington on Monday morning, according to his public White House schedule.
ANI said no injuries had been reported.