John Kerry
John Kerry Reuters

An Iranian nuclear agreement is possible this week if Iran makes the “hard choices” necessary, but if not, the United States remains ready to walk away from the negotiations, Secretary of State John Kerry said Sunday, according to Reuters.

Speaking after his third meeting of the day with Iranian Foreign Minister Mohammad Javad Zarif, Kerry said they had made “genuine progress” in talks over the last few days but “several of the most difficult issues” remain, the report said.

“If hard choices get made in the next couple of days, made quickly, we could get an agreement this week, but if they are not made we will not,” he said, speaking outside the hotel where talks between Iran, the United States and five other powers are being held.

Iran and the six world powers continue intensive talks aimed at reaching a permanent nuclear deal by Tuesday, a deadline that was decided upon after the sides had already extended the talks several times and failed to reach an agreement.

Kerry said negotiators were still aiming for that deadline, but other diplomats have said the talks could slip to July 9, the date by which the Obama administration must submit a deal to Congress in order to get an expedited, 30-day review.

President Barack Obama’s administration, which has been accused of making too many concessions by Republican members of Congress and by Israel, remains ready to abandon the talks, Kerry said.

“If we don’t have a deal and there is absolute intransigence and unwillingness to move on the things that are important for us, President Obama has always said we’re prepared to walk away,” he said, according to Reuters.

Shortly after the deadline was extended from June 30 to July 7, Obama had indeed warned Iran he is still willing to walk away from a potential nuclear deal if Tehran doesn't agree to a verifiable inspections process of its nuclear sites.

The diplomats from both sides met for a sixth consecutive day on Sunday to try to resolve obstacles to a nuclear accord, including when Iran would get sanctions relief and what advanced research and development it may pursue.

While they have made some progress on the type of bilateral sanctions relief that Iran may receive, the two sides remain divided on such issues as lifting United Nations sanctions and on its research and development of advanced centrifuges, according to Reuters.

“Many of the issues related to sanctions have been resolved, and there are four or five issues that remain including the important topic of ensuring both sides’ steps correspond to each other and happen at the same time,” Iranian Deputy Foreign Minister Abbas Araqchi was quoted as saying by the ISNA news agency.

Diplomats close to the negotiations have said they had tentative agreement on a mechanism for suspending U.S. and European Union sanctions on Iran.

But the six powers had yet to agree with Iran on a United Nations Security Council resolution that would lift UN sanctions and establish a means of re-imposing them in case of Iranian non-compliance with a future agreement.

Meanwhile on Sunday, Zarif confirmed that some differences still remained between his country and the six powers.

"Still nothing is clear ... some differences remain and we are trying and working hard," he told reporters.