A man wearing a homemade pipe bomb set off the explosive in a busy transit hub on Monday, injuring five and setting off panic during the morning commute.

Authorities said the explosion in a walkway below Port Authority Bus Terminal was an isolated attempted terrorist attack. Officials said the suspect, 27-year-old Akayed Ullah, pledged allegiance to ISIS and said he acted in response to Israeli actions in Gaza.

Investigators said the suspect had at least two devices, a law enforcement source with knowledge of the investigation told CNN. The device that detonated was a foot-long pipe that contained black powder, a battery, wiring, nails and screws. It was attached to Ullah with Velcro and zip ties. Investigators did not elaborate on the second device, the source said.

The explosive chemical ignited in the pipe but the pipe itself did not explode, lessening its impact, New York Gov. Andrew Cuomo told CNN’s Wolf Blitzer.
“Fortunately for us, the bomb partially detonated,” he said. “He did detonate it, but it did not fully have the effect that he was hoping for.”