The FBI are seeking to trace two men who allegedly removed an unexploded device from a suitcase in New York on Saturday.
Detectives said they would like to speak to the men and recover the luggage.
The undetonated device was safely removed from 27th Street in Chelsea by a bomb squad.
Authorities are investigating whether Ahmad Rahami, who was not on US counter-terrorism lists, acted alone or as part of a terror cell.
Investigators studying CCTV footage may have identified the same man at each location, law enforcement sources reported to have said.
At least 29 people have been injured in an explosion which rocked Manhattan. Here's what we know so far.