FBI investigators were examining remnants of the bomb plus an unexploded device found four blocks away and another device that exploded in New Jersey on Saturday to see if they were connected, Cuomo said.
"At this time there is no evidence of an international terrorism connection with this incident, but it is very, very early in the investigation and it's just starting," Cuomo told reporters, reiterating what Mayor Bill de Blasio had said just hours after the blast.
Some 1,000 additional state police and national guard officers were being sent to the city to patrol transportation hubs as a precaution, Cuomo said.
The U.S. Federal Bureau of Investigation (FBI) was taking evidence from all three sites to its special crime laboratory in Quantico, Virginia, said Cuomo, adding that he had been briefed by "all the relevant agencies."
"We will find who planted these explosives and they will be punished. We will not allow these type of people and these type of threats to disrupt our life in New York," Cuomo said.
Most of the injured were treated for minor injuries including shrapnel wounds, though police listed one injury as serious. Cuomo said all had been released from hospital.
