It's the off-the-cuff remark that's really got Americans jittery. President Obama raises the specter of a nuke disaster in New York City. It came during the nuclear summit being held in the Netherlands.
The president was asked this question by ABC correspondent Jonathan Karl: "Do you think Mitt Romney had a point when he said, 'Russia is America's biggest geo-political foe?' If not Russia, than who?"
Obama replied, "I continue to be much more concerned when it comes to our security with the prospect of a nuclear weapon going off in Manhattan."
There's been swift reaction to the president's new comment, which comes on the heels of recent security breaches at One World Trade Center in lower Manhattan.
Robin Roberts said on Good Morning America, "A nuclear weapon here in Manhattan. It is something else, terrifying."
INSIDE EDITION spoke to Rudy Giuliani who said, "I think the president is correct. One would say, 'Does it make people nervous to say it?' I think they should be aware of it."
Former New York City Police Commissioner Ray Kelly told INSIDE EDITION, "I am just happy that the president sees New York City as a target, because it is a target."
The White House says the president was not referring to any new or specific nuclear threat.
An NYPD spokesman says, "There are currently no known threats of this nature against the city."
Fears of a nuclear holocaust are a reoccurring fear in American life. So, what should you do if, heaven forbid, you find yourself in the aftermath of a nuclear blast?
Surprisingly, the government says, don't flee. The newest official guidelines say that finding somewhere secure to hide, or "sheltering in place," is the best way to avoid the fallout that will follow a nuclear blast. Stay there until officials tell you it's safe to come out.
Irwin Redlener is a disaster preparedness expert at Columbia University. He told INSIDE EDITION you should find shelter in the core of a building, away from all windows.
He said, "It is not all that attractive, but there are no windows, there is a lot of distance between us and the outside."
An underground parking lot or basement is also a good place to seek shelter.
Authorities say there's even a special way to shower if you think you've been exposed to fallout. Federal guidelines say you should bend your head forward to direct water away from the body. Use a sponge or washcloth, not just soap, as they're more effective in removing fallout. Tips that we pray you will never need