More details are expected Monday regarding the investigation into an improvised explosive device recovered from outside Gracie Mansion during dueling protests over the weekend. Two men, ages 18 and 19, were arrested, both apparently having traveled from Pennsylvania. Investigators are looking at the IED toss as a potential act of terrorism in part because one of the suspects directly referenced ISIS in statements to law enforcement, multiple people familiar with the matter said. The device was one of two ignited during dueling protests outside the official residence of Mayor Zohran Mamdani on Manhattan’s Upper East Side. Police officials say that had the device gone off as intended, it could have caused grave injury or even death. Tests are ongoing regarding the other device. It happened during an anti-Islam demonstration led by conservative influencer Jake Lang, and a much larger group of counterprotesters. Mamdani and first lady Rama Duwaji, who are Muslim, were home at the time. Mamdani condemned the action in a statement Sunday. Over the weekend, Tisch identified the suspects as Emir Balat and Ibrahim Kayumi. The men, ages 18 and 19, were being interviewed by the NYPD and FBI. He, alongside NYPD Commissioner Jessica Tisch, are expected to hold a press conference with an update on the case Monday morning. In a social media post over the weekend, Tisch confirmed the preliminary analysis of one of the devices showed it could have exploded. “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. It is, in fact, an improvised explosive device that could have caused serious injury or death,” Tisch in the Sunday post. She also identified the suspects as Emir Balat and Ibrahim Kayumi. It wasn’t clear if they had attorneys. Meanwhile, investigators were still conducting an analysis on a second device recovered Saturday. The FBI is also investigating. What happened at Gracie Mansion on Saturday? The two protest groups were initially divided by police, separated by barriers, before tensions escalated. Around 12:30 p.m., Tisch said an 18-year-old counterprotester “lit and threw an ignited device toward the protest area.” Witnesses said the device was smoking but extinguished itself after hitting a barrier and landing a few feet from police, the commissioner said Saturday. The 18-year-old grabbed a second device from a 19-year-old man and lit that one too, before dropping it. No one was injured by either device, police said. Police have said the men were counterprotesters to Lang’s protest, called “Stop the Islamic Takeover of New York City, Stop New York City Public Muslim Prayer.” Overall, six people were arrested as a result of Saturday’s protest — the two men “responsible for handling and deploying the devices,” the person who deployed pepper spray and three others related to disorderly conduct and obstructing traffic, Tisch said. This story uses functionality that may not work in our app. Click here to open the story in your web browser. ...read more read less