A bomb that exploded in New York City was an act of terrorism, Governor Andrew Cuomo said, but no link to international groups has been found.
Mr Cuomo said significant damage had been caused and “we were lucky there were no fatalities”. Saturday night’s blast in Manhattan injured 29 people, BBC reported.
Some 1,000 extra security personnel are being deployed in NY transport hubs.
Mr Cuomo said: “Whoever placed these bombs – we will find them and they will be brought to justice.”
The bomb exploded some days to the 71st session of the United Nations General Assembly scheduled to begin today.
A second device, a pressure cooker attached to wiring and a mobile phone – had been found four blocks from the site of the explosion in the Chelsea district and was removed safely.
But he said that, as yet, no international organisation such as so-called Islamic State had claimed they were behind it.
Mr Cuomo said: “We will not allow these type of people and these type of threats to disrupt our life in New York. This is freedom. This is democracy, and we are not going to allow them to take that from us.
“They want to instil terror. They want to make you worry about going into New York. We’re not going to let them instil fear.”
All 29 injury victims had now been released from hospital, he said.
Mr Cuomo said that the attack was one of the “nightmare scenarios” a governor must face, but he added: “We have no reason to believe at this time that there is any further immediate threat.”