NEW YORK — Get used to it — and avoid upper Fifth Avenue.

That was the message to Fifth Avenue retailers Friday from Mayor Bill de Blasio as he and New York City Police Commissioner James O’Neill discussed the security situation in and around Trump Tower, residence of President-elect Donald J. Trump that also is near to some of the street’s leading retailers.

O’Neill said the heavy security in front of Trump Tower will remain in place until Trump takes the oath of office on Jan. 20. After that, it will be reevaluated and may be loosened a bit once he is living in Washington.

And at a press conference with O’Neill at One Police Plaza Friday afternoon, de Blasio more or less recommended that “to the maximum extent possible,” people should “avoid the immediate area around Trump Tower,” saying it would “make life easier.”

He singled out 53rd to 57th Streets between Madison and Sixth Avenues as potential problem areas. That area is home to stores from Gucci to Tiffany, Bergdorf Goodman to Prada.

De Blasio’s statement Friday came after the mayor had already dismissed concerns over the impact on retailers of the security cordon around Trump Tower. A few days before, he had said that, “I will not tell you that Gucci and Tiffany are my central concerns in life,” while last week he said that the disruption wouldn’t be a problem since Midtown Manhattan would be a mess anyway because of the holiday season.

On Friday, O’Neill said Trump Tower is now seen as a terrorist target and the city and the Secret Service are determined to protect it from potential attacks. That means the metal and concrete barricades, the lane closures and the permanent shutdown of 56th Street between Fifth and Madison Avenues are now the new reality.

“We have to strike that balance between security and making sure all New Yorkers are able to get around that very busy area of the city,” he said, stressing, “We are not closing Fifth Avenue on any permanent basis.”

Workers and shoppers will be allowed access to the retail stores in the area, but those attempting to get into Trump Tower will be subjected to screening, including bag searches, the commissioner said.

Additionally, the truck ban on Fifth Avenue will be enforced. No trucks will be allowed on Fifth Avenue from 55th to 60th Streets, or on 56th between Sixth and Madison.

Bob Louttit, executive vice president of the Fifth Avenue Business Improvement District, said there has “always been a ban on trucks on Fifth Avenue, but it hasn’t always been enforced. So the retailers have the [delivery] guys come in on the side streets and walk the stuff in.”

At the press conference, the speakers were standing against a backdrop of four enormous video surveillance screens of Trump Tower and the surrounding streets. A map of the area, complete with the names of businesses and a red teardrop designating Trump Tower, filled another screen.

De Blasio called it an “unprecedented challenge” to have a president-elect living in New York City, and “entering the holiday season adds a layer of complication.” He added that “in the modern world, we’ve never had a situation where the President of the United States would be here on a regular basis” and his “focal point” would be Midtown Manhattan.

But he said the city’s number-one priority is the safety and security of both Trump and his family as well as New York’s residents and visitors. “We believe we can balance that, and keep pedestrian and vehicular traffic moving,” he said.

NYPD Chief of Department Carlos Gomez detailed the security measures that have been implemented since the election. These include uniformed officers on duty 24-hours a day, screening checkpoints on Fifth Avenue in front of Trump Tower, blocker vehicles and “Delta” barricades on 56th Street between Fifth and Madison, explosive-sniffing dogs, radiation detectors and officers stationed on observation posts on rooftops and other positions.

The BID executive said his group has already met with the NYPD and the Secret Service and expects to have another meeting in the next week or so, one that will include some of the retailers in the area “so everyone is fully informed.”

The press conference also addressed security concerns about the Macy’s Thanksgiving Day Parade. The city said security will remain the same as in the past with some adjustments including additional vehicular closures of 42nd and 57th Streets, extra sand trucks and blocker cars, and more officers on rooftops and on the route.

Reports surfaced earlier this week that ISIS is encouraging its followers to stage attacks at the parade.

De Blasio said that there were similar threats last year that caused the city to be “especially vigilant,” but the event turned out to draw the largest crowd in its history.