New York City Mayor Bill de Blasio (D) intends to ask the federal government to shoulder some of the costs that the New York Police Department has incurred with its around-the-clock security detail for President-elect Donald Trump.

“This is a very substantial undertaking,” de Blasio told reporters Friday, according to CNBC. “It will take substantial resources, and we will begin the conversation with the federal government shortly on reimbursement for the NYPD for some of the costs that we are incurring.”

“We are particularly concerned about overtime costs, and we think it’s a very valid situation to turn to the federal government for the maximum possible reimbursement for those costs,” he said.

The police department has added 50 additional officers to each daytime shift to help deal with traffic problems created by the shutting down of Fifth Avenue where Trump Tower is located, de Blasio said.

“We owe that to the president-elect, his family, his team, and that is important for all New Yorkers so that will be the most important consideration, but we believe we can balance that with a number of measures to keep traffic — both pedestrian and vehicular traffic — moving as well as possible,” the mayor added.

He also advised people in the city to avoid the area.

“To the extent you can avoid the immediate area around Trump Tower, that will make your own life easier and everyone else’s life easier,” he said. “We are devoted to making sure this city will keep moving. This is a big challenge and an unprecedented challenge, we know that, but we are committed to making it work.”