An official from the US Department of Homeland Security has suggested the bombs left in Manhattan and Elizabeth, New Jersey over the weekend were linked.
Officials had previously declined to make a firm connection between the blast which took place in the Manhattan district of Chelsea on Saturday, injuring 29 people, and Sunday's discovery of five bombs at a station in the town of Elizabeth, one of which exploded when a bomb squad robot attempted to disarm it.
New York governor Andrew Cuomo has also said that he believes the Manhattan bombing could be a terrorist act with a foreign connection.
The authorities had earlier released a picture of a man they are seeking in connection with the Manhattan blast. The FBI said the last known address of Ahmad Khan Rahami, a naturalised American of Afghan descent, was Elizabeth.
The FBI says the man should be considered armed and dangerous, he is described as being 5 foot 6 inches tall and having brown eyes, hair and facial hair.
It has been reported that investigators believe the same man may have been seen on CCTV in both locations.