A second terrorist attack struck New York City in as many months on Monday when police say a man wearing an explosive device detonated his bomb inside the subway system.

Surveillance video of the explosion shows people running from a cloud of white smoke in a pedestrian tunnel underneath the Port Authority Transit Terminal on the city’s West Side around 7:30 a.m. No serious injuries were reported, authorities said.

“This was an attempted terrorist attack,” said Mayor Bill de Blasio in a morning press conference.

The attack comes a little more than a month after a New Jersey man inspired by ISIS allegedly killed eight people with a truck by driving down a bicycle path in Lower Manhattan.

Police took suspect Akayed Ullah into custody for the bombing, NYPD Commissioner John O’Neill told reporters. Ullah had the pipe bomb strapped to his body when it went off in a passageway between two subway platforms, NYPD official John Miller said. (Police stripped Ullah to remove the device, The New York Times reported.) Ullah is being treated for burns and lacerations at a hospital, authorities said.

Ullah, 27, resides in Brooklyn and came to the United States approximately seven years ago, a U.S. official told The Daily Beast. He came to the United States from Bangladesh on a family reunification visa, according to Department of Homeland Security.

Ullah’s driver’s license allows him to drive for-hire vehicles. The New York City Taxi & Limousine commission said Monday that they had a former license under Ullah’s name. His license has been lapsed since it expired in 2015.

Raf Noboa was in the pedestrian tunnel beneath the Port Authority complex when he heard what he described as a “muffled sort of thud,” like “something big toppled over,” he told The Daily Beast.

Half-asleep, the sound didn’t register to 41-year-old Noboa. An Army veteran of Iraq, Noboa had spent much of 2004 at a logistics point near the Balad air base that was so frequently attacked it became colloquially known as Mortaritaville. Noboa didn’t so much as turn his head at the noise, he said.

“I know what an explosion sounds like. It didn’t sound like an explosion to me,” Noboa told The Daily Beast.

But he didn’t get far down the tunnel when he saw a “wave” of people running in his direction, toward the exits. No one he could hear was screaming in pain, nor did he see anyone injured. The situation might have been ambiguous, but the runners were not.

“I saw people going, ‘Go, go, go, go, go.’” Noboa went.

By the time Noboa got out onto the street, police and firefighters were swarming to the scene “like ants on sugar.”

After watching the crush of law enforcement for a bit and not seeing anyone hurt, Noboa realized that he wasn’t getting to his destination of Washington, D.C., on Monday morning. Like millions of other New Yorkers on the morning of the bombing, Noboa figured he might as well go in to work.

Police arrived outside the suspect’s Flatlands home at around 8:30 a.m., neighbors told The Daily Beast. By 9:30 a.m., neighboring homes were evacuated, said Kisslyn Joseph, 19, who lives just one door down from him.

Three people were taken out of the house and placed in a car, neighbors said.

Joseph said the neighborhood is quiet, as is the family that lives with Ullah. That’s why she took note of loud arguing coming from his home early Sunday morning.

A clerk at a deli across the street, meanwhile, said that while he didn’t know the suspect, his family was nice.

“I see the mom, she’s a very nice lady, the dad is very nice,” he said. The clerk declined to give his name.

—with additional reporting by Brandy Zadrozny