Improvised explosive devices thrown during protests outside New York Mayor Zohran Mamdani’s home are being investigated as an act of “ISIS-inspired terrorism”, police said.

The city’s police commissioner, Jessica Tisch, said the explosives could have caused serious injury or death, and were hurled during clashes between two rival groups on Saturday near Gracie Mansion.

Two men were arrested in relation to the homemade devices that were thrown during an anti-Muslim demonstration led by the far-right activist Jake Lang, which also attracted a larger group of counter-protesters.

In a statement to reporters on Monday, Mr Mamdani named the two suspects as Emir Balat and Ibrahim Kayumi, and said they had travelled from Pennsylvania.

“They are suspected of coming here to commit an act of terrorism. There is video of these two individuals throwing two devices towards the protest,” he added.

Ms Tisch said there was no apparent link to Iran or the war, but her officers were working with federal prosecutors and the FBI and “this is being investigated as an act of ISIS-inspired terrorism”.

She declined to say more about why authorities believe the suspects were motivated by the Islamic State terrorist group.

Two homemade devices, which did not explode, were thrown during the “Stop the Islamic Takeover of New York City” protest, and a third suspicious device tested negative for explosive material, she said.

At least one of the devices contained TATP, a dangerous and highly volatile homemade explosive.

Police have also been searching two locations in northeastern Pennsylvania in relation to the two suspects.

Four other people were arrested in connection with the disturbances on Saturday, including a suspect who deployed pepper spray and three others for disorderly conduct and obstructing traffic.

Later the next day, investigators found another suspicious package in a car a few streets from the mayor’s Gracie Mansion in Manhattan’s East End Avenue, and a Honda Civic was towed away.

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Mr Mamdani, a Democrat and the first Muslim to become New York mayor, and his wife, Rama Duwaji, were not at Gracie Mansion at the time of the protest.

On Sunday, Mr Mamdani condemned Mr Lang’s demonstration but said the violence ​that followed it was more disturbing.

A person linked with Mr Lang’s protest was one of the arrested suspects and charged with reckless endangerment, assault and unlawful possession of a noxious matter after allegedly macing counter-demonstrators, police said.

Mr Lang was previously charged with assaulting an officer with a baseball bat, civil disorder and other crimes before being pardoned as part of Donald Trump‘s sweeping act of clemency for defendants connected to the January 6 riots in Washington DC.