Two abandoned objects that looked like pressure cookers prompted an evacuation of a major lower Manhattan subway station during the morning commute Friday before police determined they were not explosives.
Authorities were investigating whether they were deliberately placed to spark fear.
"The suspicion is that they were placed there to suggest that they were electronic devices and possible bombs," Gov. Andrew Cuomo said on WCBS-AM.
Mayor Bill de Blasio tweeted that an investigation was continuing.
Police swarmed the find around 7 a.m. at the Fulton Street station, a few blocks from the World Trade Center. Dozens of suspicious packages are reported daily in New York City, but the proximity to the site of the Sept. 11 attacks served to heighten anxiety before police gave the all-clear.
"This is a frightening world we live in, and all of these situations have to be taken seriously because God forbid one day ... it's a real device." Cuomo said. "We learned the hard way after 9/11, and we are prepared."
Michael Oji, a New Jersey resident who works in lower Manhattan, said he's lived in the metro area for more than 20 years and saw the additional security that came to the area after the Sept. 11 attacks.
"This is supposed to be the safest part of the world, but when you see this, it's a little bit unnerving," he said just outside an entrance to the station that had been closed off by armed officers. "Going to work in the morning, thinking that everything's OK, and you run into something like this, it's scary."
De Blasio thanked both police "and everyone who kept calm through this."
New York Police Department Counterterrorism Chief James Waters tweeted photos of the objects, which looked like pressure cookers.
In September 2016, a pressure-cooker bomb went off in Manhattan's Chelsea neighborhood, injuring 30 people. The bomber, Ahmad Khan Rahimi, also planted a second pressure-cooker bomb nearby that never exploded and a small pipe bomb that went off along a Marine Corps road race in Seaside Park, New Jersey, frightening participants but injuring no one.
The Afghanistan-born Rahimi, who had been inspired by propaganda from al-Qaida and the Islamic State group, was convicted and sentenced to life in prison.
In 2017, would-be suicide attacker Akayed Ullah set off a homemade pipe bomb in an underground passageway at the Times Square subway station during rush hour, seriously injuring himself.
Prosecutors said the Bangladeshi-born Ullah was stirred by Islamic State, but he said he was angry at President Donald Trump over his Middle East policies.