A New Zealander living in New York near where a bomb injured 29 people felt his 10th floor apartment shudder from the explosion.
An extra 1000 security personnel have been deployed in the city after what the local mayor is describing as an obvious act of terrorism.
A second similar device, which did not go off, was found nearby.
Jarrod Laban was at home on the 10th floor when the blast occurred, and said he heard a "loud, extended thud".
He told Morning Report he felt an intense vibration through the building, and when he looked outside, he saw smoke and dust down the street
"There were people running everywhere, sirens going off, and police just swarming on the area. It was very chaotic, certainly from a bird's eye view."
Mr Laban said police cordons remained in place on the street.
The motive behind the bombing was still unknown and nobody had claimed responsibility for the blast.