US President Donald Trump has endorsed Andrew Cuomo in the New York City mayor's race, urging voters not to elect left-wing front-runner Zohran Mamdani.

"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 posted on Truth Social on Monday evening. "He is capable of it, Mamdani is not!"

The president earlier said he would be reluctant to send more than "the very minimum" level of federal funding to his hometown of New York if Mamdani was elected.

This echoed comments he made in a television interview on Sunday, during which he referred to Mamdani as a communist - a label that Mamdani rejects.

"It's gonna be hard for me as the president to give a lot of money to New York," Trump said in the interview. "Because if you have a communist running New York, all you're doing is wasting the money you're sending there".

Responding to Trump's comments about funding, Mamdani said he would "address that threat for what it is: it is a threat. It is not the law."

He describes himself as a democratic socialist, and has rejected accusations he is a communist, joking in one television interview that he was "kind of like a Scandinavian politician", only browner.

The Trump administration has repeatedly tried to cut federal grants and funding for projects primarily located in Democratic-run areas. New York City received $7.4bn (£5.7bn) in federal funding this fiscal year.

Independent candidate Cuomo, a long-term Trump critic who was formerly a Democratic governor for New York state, responded to the tepid backing from the president: "He's not endorsing me. He's opposing Mamdani."

Opinion polls suggest Mamdani, the Democratic nominee, is ahead of Cuomo, who is running as an Independent after Mamdani bested him in the Democratic primary. The Republican candidate, Curtis Sliwa, trails behind.

Trump, also a Republican, declined to endorse Sliwa in Monday's social media post, saying: "A vote for Curtis Sliwa ... is a vote for Mamdani."

Mamdani said that "the MAGA movement's embrace of Andrew Cuomo is reflective of Donald Trump's understanding that this would be the best mayor for him".

"Not the best mayor for New York City, not the best mayor for New Yorkers, but the best mayor for Donald Trump and his administration," Mamdani said.

In his wide-ranging interview with CBS programme 60 Minutes on Sunday, Trump said that Mamdani in office would make left-wing former New York City Mayor Bill de Blasio "look great".

"I got to see de Blasio, how bad a mayor he was, and this man will do a worse job than de Blasio by far," the president said.

Trump grew up in the New York borough of Queens and still owns property in the city.

"I'm not a fan of Cuomo one way or the other, but if it's gonna be between a bad Democrat and a communist, I'm gonna pick the bad Democrat all the time, to be honest with you," the Republican president told CBS.

If Mamdani wins, he will become the city's first Muslim mayor and its youngest in more than 100 years.

The 34-year-old state assemblyman has called Cuomo, the former New York governor, a puppet and parrot of Trump.

"The answer to a Donald Trump presidency is not to create its mirror image here in City Hall," Mamdani said on Monday.

"It is to create an alternative that can speak to what New Yorkers are so desperate to see in their own city and what they find in themselves and their neighbours every day - a city that believes in the dignity of everyone who calls this place home."

Cuomo has sought to parry that line of attack by presenting himself as the only candidate experienced enough to deal with the Trump administration.

He was governor of New York state during the Covid-19 pandemic when many states clashed with the Trump administration, though Cuomo himself came under scrutiny after state investigators found nursing home deaths were significantly understated during the outbreak.

"I fought Donald Trump," Cuomo said during a recent debate ahead of the mayoral vote. "When I'm fighting for New York, I am not going to stop."

Trump has deployed National Guard troops to Democratic-led cities as part of a crime crackdown, while seeking to strip funding from jurisdictions that limit their co-operation with federal immigration authorities.