Thomson Reuters
New York City Mayor Bill de Blasio.
The skyscraper in Manhattan was partially cleared out after a "suspicious package" - which turned out to be a bag of children's toys - was found in the lobby.
"Back to work here at Trump Tower after a false alarm. Thanks NYPD," said Sean Spicer, Trump's incoming press secretary and communications director, on Twitter.
"No problem. We'll send you the bill," Eric Phillips, spokesman for New York Mayor Bill de Blasio - quickly fired back.
De Blasio sought federal funding last month to help New York pay for Trump's security detail, which reportedly costs the city $1 million per day. Protection services will continue after Trump is inaugurated in January, as Melania Trump said she and her son, Barron, will remain in Manhattan until Barron finishes his school year.
Since Election Day, increased security around Trump Tower has brought Midtown Manhattan's already-clogged streets and sidewalks to a near-standstill.