What if Donald Trump wants to live in Trump Tower and not the White House?

New York: What if speculation proves correct and Donald Trump decides against settling in Washington and maintains his principal residence in New York?

That's the question the city's mayor Bill de Blasio raised on Friday.

Since his election last week, the real estate billionaire – who has always lived in New York – has hardly left Manhattan.

He has spent most of the time entrenched with his family and advisors in his Fifth Avenue building, Trump Tower, causing havoc in the heart of the country's largest city due to his security detail and ongoing anti-Trump protests.

"We have never faced that situation before," De Blasio told reporters.

Although he provided no concrete figures, De Blasio said security for the president-elect has been more formidable than during the annual UN General Assembly, which brings together dozens of world leaders.

City authorities -- who expect Trump to remain in Manhattan as the holidays approach -- plan to reinforce security measures and traffic restrictions already in place around Trump Tower until his inauguration in Washington on January 20.

And what afterwards?

De Blasio, who met Trump in his tower on Wednesday, refused to speculate.

"The president elect has to get into office and have the experience of being in the White House and make the decision that's right for him and his family," he said.

"When the president-elect takes on the role of president of the United States and has that responsibility, the need to be in Washington and deal with situations that can only be handled from the White House will become quite frequent," he added. "But it's not right to prejudge."

Whatever happens, De Blasio did not hide the fact that he hopes to limit the cost and recuperate the "maximum" possible reimbursement from the federal government.

Apart from the additional police and anti-terrorist units deployed 24 hours a day around Trump Tower, De Blasio highlighted the loss of revenue suffered by area businesses due to traffic jams and anti-Trump demonstrations.

And he called on New Yorkers to avoid the area as much as possible when driving or riding in cars.