Just moments after Zohran Mamdani won his battle to become the next mayor of New York City, the rising political star zeroed in on his next fight: taking on the president of the United States.

In his victory speech on Tuesday, Mamdani turned to the cameras to directly taunt the president: "So Donald Trump, since I know you're watching, I have four words for you: turn the volume up," he said.

Minutes later, Trump responded on his social media site Truth Social: "…AND SO IT BEGINS!"

President Donald Trump has decried the 34-year-old as the "communist" future of the Democratic Party.

Trump had endorsed Andrew Cuomo - a former Democratic governor who was running as an independent - and told New Yorkers that if they chose Mamdani, he would cut funding to the city. The morning after Mamdani won, he warned that people would "flee" New York.

It is not the first time Trump, a born and raised New Yorker, has tried to meddle in the city's affairs, from ramping up immigration raids to attempting to cancel funding for congestion pricing, a policy he opposes.

"If anyone can show a nation betrayed by Donald Trump how to defeat him, it is the city that gave rise to him," he said during his victory speech.

Since coming into office, Trump has wielded federal power against several Democratic-run cities, sending national guard troops and cracking down on immigration across the US.

He has also cut billions of funding to cities since the government shut down on 1 October, including New York, where he froze $18bn (£13.6bn) in federal money for major infrastructure projects.

Political experts told the BBC Trump could easily slash more - and that could hamper Mamdani's campaign promises to reduce the cost of living.