If Mamdani wins the election, Trump said on Truth Social it was “highly unlikely that I will be contributing Federal Funds, other than the very minimum as required.”

Polls show Mamdani to be leading against Cuomo, who is running as an independent after losing to Mamdani in the Democratic primary, and Republican nominee Curtis Sliwa.

Trump said a vote for Sliwa would only help Mamdani and urged his supporters to back Cuomo.

“Whether you personally like Andrew Cuomo or not, you really have no choice. You must vote for him, and hope he does a fantastic job,” Trump wrote.

Republicans have attacked Mamdani’s candidacy throughout the campaign, with Trump casting the self-described democratic socialist as a communist.

Mamdani, a Uganda-born state assembly member, shocked political observers on June 24 with a convincing victory in the primary.

Mamdani’s policies include hiking taxes on New York City’s wealthiest, raising the corporation tax rate, freezing stabilised apartment rental rates and increasing publicly subsidised housing.

His rise presents both risks and rewards for the national Democratic Party, which acknowledges the need to appeal to young voters but is wary of Republican attacks over Mamdani’s criticism of Israel’s occupation of Palestinian territories and his Democratic socialism, which has worried New York’s finance community.

Trump has used the threats of federal funding cuts throughout his second term in office over climate initiatives, transgender policies, pro-Palestinian protests against Israel’s war in Gaza and diversity, equity and inclusion practices.