US President Donald Trump has launched a blistering attack on Zohran Mamdani, the Democratic candidate for New York City mayor, branding him a “pure and terrifying communist” and warning that his election would be disastrous for the city and the country.

Speaking on Fox News’ Sunday Morning Futures, Trump didn’t hold back, saying: “If he [Mamdani] becomes mayor while I’m president, he’ll have to make the right decisions — otherwise New York won’t get a penny in federal funding.”

Trump went further to mock Mamdani’s popularity, claiming, “I hear he’s a crazy person. And if New Yorkers are actually voting for him, then I guess the entire city has gone insane.”

Calling Mamdani’s rise a “horrible prospect”, Trump said he once believed that America was safe from socialism, but now fears that a full-blown communist may take control of its most iconic city.

The comments come amid a surge in Mamdani’s political momentum.

The 33-year-old state assemblyman from Queens, originally from Uganda, stunned political analysts by securing 43.5% of the vote in the recent Democratic primary, ahead of 11 rivals, including former governor Andrew Cuomo, who managed only 36.4%.

Trump has previously issued warnings about withholding federal resources from New York City if Mamdani — whom he consistently refers to as a radical — is elected and doesn’t “behave appropriately.”