Five suspicious devices have been found in a backpack near a train station in New Jersey, with one exploding during attempts to disarm it.
Following the discovery, the FBI have carried out a search warrant at a premises in the city of Elizabeth.
Pictures have emerged of a raid on a fried chicken outlet close to where the devices were found late on Sunday.
Earlier, footage was released of the moment the device disappeared in a fireball, as FBI bomb squad robots moved in.
The blast came as five men were detained and questioned over a bomb attack in New York on Saturday night, which left 29 injured.
New York governor Andrew Cuomo said the investigation was moving quickly and it may “soon be targeting a person of interest”.
It has been reported the bomb that detonated in Manhattan, and another unexploded device found nearby, were both shrapnel-filled pressure cookers, similar to those used in the attack on the Boston Marathon in 2013.