The package was discovered in the lobby of the New York City skyscraper, where President-elect Donald Trump resides. He was in Florida at the time.
A video posted to Twitter by user @cielo_celest showed people dashing by elevators as a police officer swings his arm and yells, "Out! Out!"
New York Police Department Det. Hubert Reyes told CNN that the package was investigated by the department's bomb squad. The Secret Service was involved in the investigation as well, Reyes said.
"Suspicious package at Trump Tower has been examined by NYPD Bomb Squad. Deemed to be an unattended bag and safe," police tweeted. Earlier police spokesman J. Peter Donald tweeted the package was in the lobby.
Around the time of the evacuation Trump was posting on Twitter, saying, "President Obama campaigned hard (and personally) in the very important swing states, and lost.The voters wanted to MAKE AMERICA GREAT AGAIN!"
The city of New York is spending millions on security at the President-elect's building, costs it has asked the federal government to be reimbursed for, and the incident set off a Twitter spat.
Trump spokesman Sean Spicer tweeted shortly after the episode, "Back to work here at Trump Tower after a false alarm. Thanks NYPD."
Eric Phillips, spokesman for Mayor Bill de Blasio, tweeted in response, "No problem. We'll send you the bill."
That didn't sit well with Trump director of social media Dan Scavino, who retweeted the exchange with his own message: "Eric Phillips- Spokesperson for @NYCMayor @BilldeBlasio- you are an embarrassment to the @NYCMayorsOffice & the amazing #NYPD."
Phillips responded, "That's not very nice, Dan. But about that bill ... work on it with us?"
Trump Tower is on Fifth Avenue between East 56th and East 57th streets in midtown Manhattan.