Authorities are investigating potential terrorism links to two suspects in custody over what New York City Police Commissioner Jessica Tisch said was an improvised explosive thrown near Mayor Zohran Mamdani’s residence, people familiar with the investigation said.

“The NYPD Bomb Squad has conducted a preliminary analysis of a device that was ignited and deployed at a protest yesterday and has determined that it is not a hoax device or a smoke bomb,” Tisch said in a statement posted on X Sunday, adding that two individuals connected to the device are in police custody. “It is, in fact, an improvised explosive device that could have caused serious injury or death.”

While Tisch did not elaborate on the investigation, people familiar with the investigation said the suspects — identified as Emir Balat and Ibrahim Kayumi by the commissioner — told detectives they believed the leader of an anti-Muslim protest near Mamdani’s residence had insulted their religion and described the devices as retaliation. Investigators also found the men had watched Islamic State propaganda videos before the protests, the people said.

Authorities on Saturday arrested a total of six people connected to the broader unrest stemming from the anti-Muslim demonstration outside the residence near East End Avenue and East 87th Street starting at about 11 a.m. local time. Mamdani is the city’s first Muslim mayor.

Police on Saturday said an 18-year-old man threw an ignited device toward the protest area as about 20 participants in the anti-Muslim protest, organized by conservative influencer Jake Lang, clashed with a group of counter-protesters that at one point swelled to as many as 125 people at its peak.

Witnesses reported flames and smoke before that device struck a barrier and extinguished itself a few feet from police. The man then allegedly obtained a second device from a 19-year-old, lit it and dropped it on East End Avenue before being taken into custody. The incident triggered a bomb squad response and a terrorism investigation.

“The attempt to use an explosive device and hurt others is not only criminal, it is reprehensible and the antithesis of who we are,” Mamdani said in a statement Sunday, thanking the police and adding that he remains in close contact with Tisch about the situation.

Police have said the explosive devices appeared to be jars wrapped in black tape with nuts, bolts and screws attached and fitted with hobby fuses. An object of concern was found in the front passenger-side area of the suspects’ car that appeared similar to the devices recovered a day earlier, people familiar with the probe said, adding the object was taken to be examined by bomb technicians at a police facility in the Bronx.

Authorities are examining whether the pair were self-radicalized online or received outside training, the people said, adding that one of the suspects requested an attorney while being questioned.

Investigators are reviewing the two suspects’ overseas travel records to determine whether they, combined with their online activities, are relevant to the investigation. The suspects took separate trips to Istanbul in 2024 and 2025, with one suspect staying abroad for several months. One of the men also previously traveled to Australia in 2019.

Tisch told reporters on Saturday she didn’t believe Mamdani or the first lady, Rama Duwaji, were at home at the time. The New York City Police Department is working with the US Attorney’s Office for the Southern District of New York and the Federal Bureau of Investigation through the Joint Terrorism Task Force.

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