President Barack Obama says the United States would “walk away” from the talks with Iran over its nuclear program if the deal is not good enough.

Any agreement must allow the US and other powers to verify that Iran does not obtain an atomic weapon, and that even if Iran “cheated,” the U.S. and others would have “enough time to take action,” and “if we don’t have that kind of deal, then we’re not going to take it,” he told CBS‘s “Sunday Morning.”

“If we cannot verify that they are not going to obtain a nuclear weapon, that there’s a breakout period so that even if they cheated we would be able to have enough time to take action – if we don’t have that kind of deal, then we’re not going to take it,” he said.

Obama said the negotiations on Iran’s nuclear program were gaining “greater urgency because we have been negotiating for over a year.”

“And the good news is during this period Iran has abided by the terms of (an interim) agreement. We know what is happening on the ground in Iran. They have not advanced their nuclear program.

“So we’re not losing anything through these talks. On the other hand, you get to a point in negotiations where it is not a matter of technical issues any more, it is a matter of political will.”

Obama made the comments Saturday as US Secretary of State John Kerry was in Paris to discuss the nuclear talks with France, which wants stricter guarantees that the agreement will keep Iran from gaining a nuclear weapon.

“We want an agreement that’s solid,” Kerry told reporters after meeting with French Foreign Minister Laurent Fabius.

“We want an agreement that will guarantee that we are holding any kind of program that continues in Iran accountable to the highest standards so that we know in fact that it is a peaceful program.”

Fabius said Friday that “as regards the numbers, controls and the length of the agreement, the situation is still not sufficient.”