Suspects charged in alleged "ISIS-inspired" attack near NYC's Gracie Mansion. Read the criminal complaint.

New York Police Commissioner Jessica Tisch said homemade bombs ignited during protests outside Gracie Mansion on Saturday are being investigated as "an act of ISIS-inspired terrorism." 

Officials said two devices found at Mayor Zohran Mamdani's residence were improvised explosive devices, or IEDs, that could have seriously injured or killed someone. A third device is being investigated.

"This was a planned attack motivated by extremist ideology and inspired by a violent, foreign terrorist organization," Tisch said.

Teenagers charged in FBI probe

The FBI launched a terrorism investigation into the incident, and on Monday federal prosecutors in the Southern District of New York unveiled charges against 18-year-old Emir Balat and 19-year-old Ibrahim Kayumi, who were taken into custody following the chaos on Manhattan's Upper East Side.

Balat and Kayumi, both from Pennsylvania, are each charged with five counts, including attempted support to a designated foreign terrorist organization (ISIS), use of a weapon of mass destruction, and transportation of explosive materials, according to the federal criminal complaint. 

Tisch said both admitted to being inspired by ISIS. 

"As Kayumi was being placed into an NYPD vehicle following his arrest, a person in the crowd asked why he had done this. As shown on NYPD body-worn camera footage referenced in the complaint, Kayumi responded with 'ISIS,'" the commissioner said. 

Tisch said Kayumi waived his Miranda rights and told police that he watched ISIS propaganda on his phone. Balat also waived his rights and wrote a statement declaring his allegiance to the Islamic State, she said. 

"[Balat] also told investigators that he hoped to carry out an attack even bigger than the Boston Marathon bombing, which he noted resulted in 'only three deaths,'" Tisch said.

"It is chilling that they wanted to do something more than the Boston Marathon bombing," U.S. Attorney Jay Clayton said.

"This was an alleged ISIS-inspired act of terrorism that could have killed American citizens. We will not allow ISIS's poisonous, anti-American ideology to threaten this nation -- our law enforcement officers will remain vigilant, as they were when these devices were brought to a protest," U.S. Attorney General Pamela Bondi said in a statement.

When asked if Balat is a member of ISIS, his attorney, Mehdi Essmidi, said, "Not to my knowledge." He also said his client's family is distraught and had no idea the U.S. citizen and high school senior was in New York.

"There's really nothing in his history that indicated ... he used to be on his school's wrestling team, he was a good student a good son, [and] wasn't involved in anything," Essmidi said.

The two suspects made their first court appearances Monday, where the judge ordered them to remain in federal custody and set a preliminary hearing for April 8.

Legal experts say statements allegedly made by the defendants could bring great weight to the case.

"It's massively important if they are connected in some capacity to ISIS. This bring the charges up to a federal level," civil rights attorney Andrew Laufer said.

The defendants have not yet been indicted.

"It takes time to put this before a grand jury. They have to convene the grand jury. They could be charged by a criminal complaint, but my feeling is that they are gonna be put in front of a grand jury at some juncture," Laufer said.

Read the criminal complaint

Clashing protests escalated outside Gracie Mansion

Before the charges were filed, Tisch and Mamdani spoke at a news conference, commending the officers who responded over the weekend. 

"They faced a chaotic situation that very quickly could have become far more dangerous. NYPD Chief Aaron Edwards and Sgt. Luis Navarro ran towards the danger so others could run towards safety," Mamdani said.

An anti-Islam protest with about 20 participants was organized by people associated with Jake Lang, a pardoned Jan. 6 rioter and far-right influencer, Tisch said. They arrived outside Mamdani's Upper East Side home at around 11 a.m. on Saturday.

A counterprotest drew more than 100 participants to the area. Tensions started to escalate just after noon.

Tisch said Balat and Kayumi arrived in New York City one hour before they were arrested, crossing the George Washington Bridge at 11:36 a.m., adding they parked at 12:05 p.m. and then walked to the protest.

An individual from the initial protest used pepper spray against the counter-protesters, officers said. Shortly after 12:30 p.m., a counter-protester, identified as Balat, lit and threw an ignited device at the anti-Islam protesters, according to police.

Balat then retrieved a second device from Kayumi and lit it, before running and dropping it, investigators said.

They were arrested outside Gracie Mansion. Tisch said they would be prosecuted in federal court.

An attorney for one of the accused said Balat and Kayumi are from different parts of Pennsylvania and don't know each other.

"They should be held fully accountable for their actions"  

Mamdani and his wife were not at Gracie Mansion at the time of Saturday's protest.

"While I found this protest appalling, I will not waver in my belief that it should be allowed to happen. Ours is a free society, where the right to peaceful protest is sacred," Mamdani said.

In an earlier statement, Mamdani said, "They should be held fully accountable for their actions. They are suspected of coming here to commit an act of terrorism."

Lang was outside Gracie Mansion on Monday after the mayor spoke.

"We support our country, we support the NYPD, and Mamdani is going to destroy the city," he said. 

NYPD Bomb Squad removed IEDs

Law enforcement sources said the devices consisted of sports drink bottles filled with explosive material and placed inside glass jars. The jars were wrapped in black tape with nuts and bolts. The fuse was connected to a firework, but officials said it could have gone off when it hit the ground.

Another suspicious device was found Sunday in a car about three blocks south of Gracie Mansion. The NYPD said it was safely removed for testing.   

Testing revealed that one of the devices deployed contained triacetone triperoxide, known as TATP.

"TATP is a dangerous and highly volatile homemade explosive that has been used in IED attacks around the world," Tisch said.  

She said there's nothing to connect the IEDs to the war in Iran, but authorities said they believe the suspects got their inspiration from other terrorist groups.