New York City Mayor Zohran Mamdani is suing President Donald Trump's administration over plans to expand federal authority to deny visa and green card applications based on welfare status.The lawsuit, filed jointly with NY Attorney General Letitia James, targets the Trump administration's plan to expand the "public charge rule," which allows the federal government to deny visa applications based on the likelihood that the applicant will receive public benefits. Trump's administration seeks to expand the list of benefits that apply under the rule, with the change taking effect Sept. 18."If you are a citizen, or an individual seeking humanitarian relief like asylum, these changes will not affect you," Mamdani said at a press conference Monday. "The new public charge rule not only sweeps aside more than a century of established law, it is intentionally vague as a means of creating uncertainty and fear to isolate immigrant New Yorkers.""Make no mistake, this is an undisguised effort to strip New Yorkers of the services they rely on, the public benefits they are entitled to," he continued.Mamdani claimed that up to 4 million people could be forced to unenroll from their healthcare under the new rule out of fear their immigration applications could be denied.Several major cities and counties across the country are joining New York's lawsuit, including Chicago, San Francisco, Seattle, Santa Clara County and King County, Mamdani said.This is a developing story. Check back soon for updates.