WASHINGTON (AP) -- President Barack Obama says the United States would "walk away" from nuclear talks with Iran if there's no acceptable deal.

Obama says any agreement must allow Western powers to verify that Tehran isn't going to obtain an atomic weapon, and that even if Iran "cheated," the U.S. and others would have "enough time to take action."

Secretary of State John Kerry, left, during a news conference with French Foreign Minister Laurent Fabius, on Saturday. (AP Photo/Evan Vucci)

The president tells CBS' "Sunday Morning" that "if we don't have that kind of deal, then we're not going to take it."

Big gaps remain to bridge if the sides are to reach a deal by the end of March deadline set by negotiators. The next round of talks is set to begin March 15.

Iran says the program is peaceful and exists only to produce energy for civilian use.

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