Barack Obama
Barack ObamaReuters

US President Barack Obama said Tuesday that he is still willing to walk away from a potential nuclear accord with Iran if Tehran doesn't agree to a verifiable inspections process that satisfies the US and the five other world powers involved in the negotiations."

"There's still some hard negotiations left to take place," he said. "Ultimately, it's going to be up to the Iranians to determine whether they meet that requirement – to be able to fairly and accurately and consistently assess whether they have foreclosed the possibility of attaining a nuclear weapon."

He spoke shortly after the State Department confirmed that the Iran talks were being extended to July 7, beyond the original June 30 deadline.

"There has been a lot of talk on the other side by the Iranian negotiators about whether in fact they can abide by some of the terms that came up in Lausanne," Obama said, referring to the framework deal reached by the US and Iran on April 2. That agreement, he said, "if implemented and codified properly, would achieve my goal, which is Iran not attaining a nuclear weapon."

"My hope is they can achieve an agreement," Obama said. "If they cannot, that's going to be a problem. Because I've said from the start, I will walk away from the negotiation if, in fact, it's a bad deal."

"If we can't provide assurances that the pathways for Iran attaining a nuclear weapon are closed and if we can't verify that [...] then we're not going to get a deal, and we've been very clear to the Iranian government about that," he continued.

Speaking in a joint press conference with Brazilian President Dilma Rousseff, Obama said that the ability to reach a nuclear accord with Iran is not based on trust, but on setting of a "verifiable" process to "cut off a pathway" for Iran to develop a nuclear weapon.

The tensions and divisions between the US and Iran are "deep-seated" and have developed over time and "aren't going away overnight," Obama added.