Anti-Muslim online posts targeting New York City mayoral candidate Zohran Mamdani have surged since his Democratic primary upset this week, including death threats and comments comparing his candidacy to the September 11, 2001 attacks, advocates said on Friday.

There were at least 127 violent hate-related reports mentioning Mamdani or his campaign in the day after polls closed, said CAIR Action, an arm of the Council on American Islamic Relations advocacy group, which logs such incidents.

That marks a five-fold increase over a daily average of such reports tracked earlier this month, CAIR Action said in a statement.

Overall, it noted about 6,200 online posts that mentioned some form of Islamophobic slur or hostility in that day long time-frame.

Mamdani, a self-described democratic socialist and a 33-year-old state lawmaker, declared victory in Tuesday’s primary after former New York Governor Andrew Cuomo conceded defeat.

Born in Uganda to Indian parents, Mamdani would be the city’s first Muslim and Indian American mayor if he wins the November general election.

“We call on public officials of every party — including those whose allies are amplifying these smears — to unequivocally condemn Islamophobia,” said Basim Elkarra, executive director of CAIR Action.

The advocacy group said its hate monitoring system includes its own scraping and analysis of posts, online submissions by the public and notifications from law enforcement. About 62 per cent of the anti-Muslim posts against Mamdani originated on X, CAIR Action said.

People close to Republican President Donald Trump, including one of his sons, are among those spreading anti-Muslim rhetoric, advocates said.

Donald Trump Jr, the president’s son, wrote on X on Wednesday that “New York City has fallen” while sharing a post that said New Yorkers had “voted for” 9/11.

Also on Wednesday, Republican US Representative Marjorie Taylor Greene posted an AI-generated picture of the Statue of Liberty draped in a burqa.

President Trump has pursued domestic policies that rights advocates have described as anti-Muslim, including banning travel from some predominantly Muslim or Arab countries in his first term and attempting to deport pro-Palestinian students in his current term.

The White House, which did not respond to a request for comment, has denied claims of discrimination against Muslims. Trump and his allies have said they oppose Mamdani and others due to what they call the Democrats’ “radical left” ideology.

Threats

The New York City Police Department said earlier this month its hate crime unit was probing anti-Muslim threats against Mamdani.

Manjusha Kulkarni, co-founder of Stop AAPI Hate, which documents hate against Asian Americans, and CAIR said attacks against Mamdani mirrored those endured by other South Asian and Muslim political figures, including former Vice President Kamala Harris and Representatives Ilhan Omar and Rashida Tlaib.

Republicans have called Mamdani antisemitic, citing his pro-Palestinian advocacy and his criticism of Israel’s military assault on Gaza after an attack by Hamas militants in October 2023.

Mamdani has condemned antisemitism and has the backing of New York City Comptroller Brad Lander, who is Jewish. Lander also ran in the Democratic primary.

Rights advocates have noted rising antisemitism and Islamophobia since the start of the Israel-Gaza war, with fatal US incidents including the shooting of two Israeli embassy staff in Washington and the stabbing of a Muslim child in Illinois.

Mamdani and other pro-Palestinian advocates, including some Jewish groups, said their criticism of Israel is wrongly conflated with antisemitism.