The U.S. Justice Department said it would sue New York City Mayor Zohran Mamdani if he tries requiring white neighborhoods to pay higher property taxes.

Harmeet Dhillon, U.S. assistant attorney general for the DOJ’s Civil Rights Division, was responding to a socal media post about a New York Post front page from the NYC mayoral campaign.

“This is illegal. If it happens, expect a lawsuit. Or many,” she wrote.

Earlier this month, Mamdani released details of his current tax plan, which includes requiring luxury second homes to pay higher property taxes.