Many in India are celebrating New York City mayor Zohran Mamdani for saying he would ask King Charles to return the Koh-i-Noor diamond, a 105.6-carat jewel that was taken from India during British colonial rule and is now part of the crown jewels.

The diamond was taken from what is now Pakistan and presented to Queen Victoria in 1849 after the Treaty of Lahore, and many in South Asia view it as one of the most prominent symbols of colonial plundering. India has repeatedly called for it to be given back, though Pakistan, Iran and Afghanistan have also laid claim to it.

The jewel’s long and contested history became an unexpected talking point during the third day of Charles and Queen Camilla’s state visit to the US, where they met Mr Mamdani during a commemorative service at the 9/11 memorial in New York.

Earlier, at a press conference, Mr Mamdani was asked by a reporter what he intended to say to the King, beyond representing New York and honouring the 3,000 people killed in the September 11 2001 attacks.

“If I was to speak to the King, separately from that, I would probably encourage him to return the Koh-i-noor diamond,” Mr Mamdani responded.

It is not known whether Mr Mamdani followed through with his remark when he actually met the King – his office has declined to confirm either way, and Buckingham Palace has declined to ​comment. The Indian government is also yet to respond officially to the remarks.

But online there was an immediate reaction, with many praising Mr Mamdani, while others suggested his attentions would be better focused on matters in New York.

X user Ratnesh Paliya wrote: “Bro quotes Nehru in victory speeches, plays Bollywood songs, and now wants the Kohinoor returned. At this point, he sounds more Indian than half of Indian Twitter.”

Another X user wrote: “LOL you can’t deny that Mamdani grew up very much in touch with his desi roots. My kids would have zero idea what the Koh-i-noor was or any knowledge of British colonial rule in India.”

“Become First Indian origin African born Mayor of NYC. Immediately asks for colonial loot to be returned to its rightful owners. Very based,” wrote another.

One user said they were “not a fan” of Mr Mamdani, “but at least he has the guts to call out [the] King of England [for] their robbery from India”.

Another commented on a video of the remarks: “Well wow, good if he is able to succeed. It’s long overdue that the Kohinoor is returned to its rightful owner.”

Others noted that Mr Mamdani conspicuously did not say that the diamond should be returned to India. “Return to whom?” wrote one user. “Many countries claim it.”

Not everyone was happy about the idea of the New York mayor making such an appeal, however. Zeba Zoariah wrote: “Koh-i-noor for us is a reminder of how power moved and wealth was taken. Urging the Crown in a New York room may sound bold for your crowd, but we get your act. Stop speaking on behalf of us. We’ve lived this history we can tell when it’s being performed.”

Amanda Foreman, a royal contributor, told CBS News that King Charles doesn’t own the Koh-i-Noor diamond.

“The King has no more power to return the diamond than he has to return Buckingham Palace to the people,” Ms Foreman said.

Some critics called Mr Mamdani’s remark undiplomatic. Republican strategist, O’Brien Murray, said asking the King to return the diamond was a “terrible idea, terrible idea”.

“As the mayor of New York, he was speaking to the king through the media. Stay out of foreign policy unless it helps all New Yorkers with your current problems.”

Ken Frydman, a Democratic operative and spokesperson for former NYC mayor Rudy Giuliani, told New York Post: “The sitting mayor of New York City shouldn’t give us a history lesson while politicising the visit of the sitting King of England. He should’ve enthusiastically welcomed him, not reluctantly.

“We know the history,” he added. “No one has forgotten colonialism.”

Meanwhile, the Manhattan district attorney’s office on Wednesday announced the return of 657 stolen antiquities worth nearly $14m to India after investigations into global smuggling networks. The items – linked to dealers like Subhash Kapoor – were recovered through ongoing probes into large-scale cultural theft. The investigation focused on tens of thousands of antiquities allegedly smuggled into the United States by Kapoor, who has denied the allegations.