A device thrown outside Gracie Mansion on Saturday during dueling protests in New York City was confirmed to be an improvised explosive device, according to police.
Two men, described by police as an 18-year-old and a 19-year-old, were taken into custody after at least one of two devices was ignited during an anti-Islam demonstration led by conservative influencer Jake Lang and a counterprotest outside the mansion, which serves as a residence for New York City’s mayor.
Police Commissioner Jessica Tisch described the devices Saturday as being smaller than a football and said they appeared to be jars wrapped in black tape with nuts, bolts, screws and a hobby fuse. Further testing was being conducted on both, she said.
A test of the explosive compound found in a container thrown by one of the men has preliminarily come back as triacetone triperoxide, or TATP, a notoriously volatile and dangerous type of homemade explosive, two people familiar with the investigation said Sunday. Follow-up tests will be conducted.
The NYPD said Sunday the investigation led officers to find a “suspicious device” in a vehicle on East End Avenue between 81st and 82nd streets. Officers conducted limited evacuations of buildings nearby as a bomb squad responded, police said.
By Sunday evening, the NYPD said that it had safely removed the device from the area for further testing and that people who were evacuated could return to their residences.
A person briefed on the investigation said a container found in a car, which they believed the men used, was concerning to investigators and that the NYPD Bomb Squad will take it to its facility at Rodman’s Neck in the Bronx.
An FBI spokesperson said the two men detained in the case are in federal custody, where they are being interviewed by federal agents and the NYPD.
“Emir Balat and Ibrahim Kayumi were arrested on scene yesterday and are in custody in connection with this matter," Tisch said Sunday on X.
Officials are working with federal prosecutors, Tisch said. It’s unclear whether the men have been charged.
The FBI's Joint Terrorism Task Force is investigating along with the NYPD and the U.S. Attorney’s Office for the Southern District of New York, the FBI said Sunday on X.
Federal and local law enforcement officers are investigating the matter as a potential act of terrorism in part because one of the men in custody directly referred to ISIS in statements to law enforcement, multiple people familiar with the matter told NBC News.
Both men are from Pennsylvania, where law enforcement officials went to speak to relatives and contacts, sources familiar with the investigation told NBC News.
Searches of both their homes and electronic devices were expected, two sources said.
On Sunday, NBC Philadelphia cameras captured law enforcement officers who appeared to be conducting searches at two separate Pennsylvania locations tied to the men’s addresses.
The Lang-led protest outside Gracie Mansion, called “Stop the Islamic Takeover of New York City, Stop New York City Public Muslim Prayer,” drew roughly 20 people, police said. The counterprotest drew about 125 demonstrators at its peak.
Police separated the groups into designated areas when the protests began at about 11 a.m. Saturday, but officials said tensions escalated within an hour.
At 12:15 p.m., a protester from the Lang group fired pepper spray at counterprotesters and was arrested, Tisch said. Then, shortly after 12:30 p.m., she said, an 18-year-old counterprotester “lit and threw an ignited device toward the protest area."
The incident occurred halfway through the holy month of Ramadan, the ninth month of the Islamic calendar, when Muslims all over the world fast from sunrise to sunset. It is meant to be a month of reflection and spiritual connection in commemoration of when the first verses of the Quran were revealed to Prophet Muhammad.
New York Mayor Zohran Mamdani, who is Muslim, was in Gracie Mansion at the time of the incident.
Mamdani thanked law enforcement officers who acted quickly and said in a statement Sunday that he was working closely with Tisch on the case.
He condemned the original event organized by Lang, whom he described as a white supremacist, as being rooted in bigotry. Such hatred “has no place in New York City,” he said.
“What followed was even more disturbing. Violence at a protest is never acceptable. 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 added.
