Zohran Mamdani, who is the Democratic candidate for New York City mayor after a stunning victory last week, has said no one should have billions of dollars.

In an interview with NBC, Mamdani also stood by his proposal to tax "richer and whiter" neighbourhoods, arguing the city's property tax system is unfair.

The 33-year-old defended his democratic socialism, rejecting an accusation from US President Donald Trump that he is a communist.

If elected in November, he would be the first Muslim and Indian American to lead the nation's largest city.

Mamdani ran an energetic campaign focused on affordability, promising free buses, universal childcare, a $30 minimum hourly wage, a rent freeze and city-run supermarkets - all paid for with higher taxes on the top 1% of earners.

On NBC's Meet the Press programme on Sunday, he was asked whether billionaires have a right to exist.

"I don't think that we should have billionaires because, frankly, it is so much money in a moment of such inequality," he replied.

New York's mayor has the power to propose a hike on property taxes, but revenue increases ultimately require approval from the state legislature and the governor.

NBC interviewer Kristen Welker asked Mamdani about a policy proposal on his campaign website to shift the tax burden "to more expensive homes in richer and whiter neighbourhoods".

Asked whether he might alienate key constituents by invoking race, he denied the policy was driven by race and said: "I think I'm just naming things as they are."

In an interview with Fox News on Sunday, President Trump threatened to cut off federal funding for New York City if Mamdani wins, calling him a "pure communist".

Mamdani denied being a communist, adding: "I have already started to get used to the fact that the president will talk about how I look, how I sound, where I'm from, who I am, ultimately because he wants to distract from what I am fighting for."

He said New York is "the wealthiest city in the wealthiest country in the history of the world, and yet one in four New Yorkers are living in poverty."

Millionaires in New York pay 41% of all personal income tax, according to the state Department of Taxation and Finance.

In last week's Democratic primary, Mamdani defeated his main intraparty challenger, Andrew Cuomo, who resigned as New York governor in 2021 after sexual harassment allegations.

Mamdani has been under scrutiny for his stance on the Israel-Gaza war, after voicing strong support for Palestinians and accusing Israel of genocide, which it denies.

He was asked about these views in the NBC interview, and whether he would condemn the term "globalise the intifada".

Many Jews argue this slogan is an antisemitic call for violence, but pro-Palestinian activists say it is a call for international solidarity with Palestinians.

"That's not the language that I use," said Mamdani, adding that he condemns antisemitism. When pressed, he said it was not the role of the mayor to "police speech".

On NBC, he sought to draw a contrast between himself and the Trump administration, whom he criticised for detaining Mahmoud Khalil, a pro-Palestinian activist at Columbia University and a lawful US resident.

Mamdani has described "globalise the intifada" in the past as "a desperate desire for equality and equal rights in standing up for Palestinian human rights".