New York City Mayor Zohran Mamdani, a Democrat, threatened to sue the Trump administration over Immigration and Customs Enforcement's (ICE) reported use of city-owned parking lots to stage immigration enforcement operations without the city's authorization.

In a letter addressed to Homeland Security Secretary Markwayne Mullin, acting ICE Director David Venturella and ICE New York field office Director Kenneth Genalo, Mamdani said he is "deeply troubled" by reports of ICE agents "using property owned by the City of New York to stage enforcement operations," which the mayor said is unauthorized and illegal.

"This use of City property in furtherance of federal immigration enforcement is unauthorized and is therefore illegal, endangers City residents, and sows fear among those who seek to access City property," Mamdani wrote in the letter. "If your agents continue any unauthorized use of these lots, New York City will take legal action to prevent this unlawful commandeering of City property."

According to the mayor's letter, ICE agents have reportedly parked their vehicles and conducted meetings in several city-owned, unstaffed parking lots, including in a parking lot at Van Cortlandt Park in the Bronx as well as in parking lots along 111th Street on the west side of Flushing Meadows Corona Park in Queens, which is located next to a city-run preschool and several cultural institutions welcome hundreds of children and families every day.

"ICE has not secured any authorization from the City to use these lots for immigration enforcement. To be clear: the City does not authorize ICE using its property in this manner," Mamdani wrote.

"Parking lots connected to City parks are reserved for the safe use and enjoyment of New Yorkers and visitors who wish to use our parks," he continued. "Use of these lots for other purposes, including ICE’s reported use of these lots, amounts to unauthorized activity on City property. Accordingly, you must immediately issue guidance to your agents prohibiting them from using any City lots to stage or conduct enforcement operations."

Mamdani added that New York City "deeply values its immigrant communities and will continue to use all available lawful means to ensure their safety, well-being, and ability to navigate the City and its resources without fear." Fox News Digital has reached out to the Department of Homeland Security for comment.

Last month, Mamdani and other New York Democratic leaders pushed for the city’s private parking lot owners to ban ICE from their properties.

"In solidarity with immigrant New Yorkers and in our shared commitment to the City we love, we ask that you do not rent, lend or otherwise make your property available to ICE as a staging area for its enforcement operations," the mayor wrote in a letter to property owners and operators.

Senate Minority Leader Chuck Schumer, D-N.Y., and House Minority Leader Hakeem Jeffries, D-N.Y., were among more than 100 elected officials who signed on to Mamdani's October letter.

Mamdani has previously pushed for ICE to be abolished, including after an ICE agent shot and killed Mexican national Lorenzo Salgado Araujo in Houston in July and after another ICE agent shot and wounded Dominican national Oscar Belgal during an enforcement operation in New York City last month.