Immigration and Customs Enforcement is exploring the possibility of leasing 249 parking spots in downtown Boston, according to a federal notice, which would represent a major boost to the agency’s visible presence in the city.

The agency issued a notice last month seeking to identify suitable parking spaces in more than a dozen cities across the country, including Boston. The prospective spaces would all be “in the vicinity of existing or planned ICE facilities.”

Proposals are due by Friday.

It’s unclear if the agency is considering opening a new facility in or around downtown Boston.

Officials said the notice was issued “solely for market research and information-gathering purposes.”

The notice solicits spaces with a leasing term of between three to five years, contiguous parking spaces, and a location within each city’s central business district.

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Of the 14 cities listed in the notice, Boston is the only one in New England. The solicitation for 249 spaces was second only to Englewood, Colo., where ICE is seeking 250 spaces.

Other cities on the list include Philadelphia (150 spaces), Pittsburgh (60), Dallas (85), Phoenix (74), St. Louis (30), and New Orleans (20).

A spokesperson for Mayor Michelle Wu said Tuesday the city opposed “any efforts to allow ICE to stage its lawless operations here,” given the agency’s “violent and deadly attacks on American cities.”

Last year, Boston banned ICE from using municipal property, such as city-owned parking lots, as staging areas for their operations. It’s not clear how, or if, those ordinances have been enforced.

Immigration agents have also been seen using other public spaces as staging areas, such as supermarket parking lots.

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ICE’s main Boston field office is in Burlington. The Department of Homeland Security also maintains offices at the Thomas P. O’Neill Federal Building, though federal officials have recently floated putting it up for sale.

Local advocates said earlier this year that more than 100 unregistered vehicles have been delivered to a parking garage near the Burlington field office, sparking fears of a surge in ICE operations.

Governor Maura Healey, ahead of signing a bill for immigration protection on Wednesday, said in a statement the agency should “keep their vehicles out of Boston.”

“We absolutely cannot allow ICE to have 250 parking spots in downtown Boston while they are engaging in these illegal tactics,” Healey said. “We cannot enable them to ramp up even further in Massachusetts.”

Lawyers and advocates in Massachusetts have said the pace of ICE arrests has escalated over the past several months. And last month, The New York Times reported that ICE had detained 10,000 people in five days, doubling the agency’s nationwide daily detention numbers.

That report came before two fatal shootings of immigrants by ICE agents, including a 25-year-old in Biddeford, Maine. In response, ICE said it would temporarily suspend vehicle stops, but the agency reversed course after President Trump voiced his support for the tactic.