Iran, U.S., World Powers reportedly reach milestone Nuclear deal; Announcement Expected Monday

They appear to have a deal.

Secretary of State John Kerry (c.) and State Department Chief of Staff Jon Finer (l.) meet with members of the U.S. delegation at the garden of the Palais Coburg hotel, where the Iran nuclear talks meetings are being held in Vienna, Austria.

After years of tough negotiations, diplomats for Iran, the U.S. and several other Western countries were on the verge of a milestone agreement to curb Tehran’s nuclear program, the Associated Press reported Sunday.

Under the deal, which is set to be announced formally late Sunday night or Monday morning, the U.S. would lift most economic sanctions on Iran in return for the country agreeing to curb its controversial nuclear program.

A few last details on the final provisional deal, however, were still being worked out Sunday, negotiators told the AP, and the official agreement will still need to be reviewed and approved by President Obama and the leaders of Iran and the other six world powers participating in the talks.

A senior U.S. official expressed caution at reports over a looming agreement, telling the AP that “major issues remain to be resolved,” but other figures were more optimistic.

U.S. Secretary of State John Kerry, who has been in Russia for 16 consecutive days feverishly negotiating, said twice that he was “hopeful” after “a very good meeting” late Saturday with Iranian Foreign Minister Mohammad Javad Zarif.

French Foreign Minister Laurent Fabius also was cautiously optimistic, telling reporters Sunday, “I hope that we are finally entering the last phase of this negotiation.”

Adding to the belief that a pact was imminent were reports from Russian media outlets saying that Russian Foreign Minister Sergey Lavrov had arrived in Vienna on Sunday, with Chinese counterpart Wang Yi expected to arrive later in the day so that a joint announcement could be made with all leaders present.

Under the general terms of the deal, long-term, verifiable limits on nuclear programs that Tehran could modify to produce weapons would be imposed. Iran, in return for agreeing to the limits, would get tens of billions of dollars in sanctions relief.

Despite the apparent breakthrough, a large number of U.S. lawmakers doubled down on criticism of any deal Sunday, blasting the reported terms and reiterating the oft-repeated talking point that no deal was better than a bad deal.

“I’m concerned about where we’re going,” Senate Foreign Relations Committee Chairman Bob Corker (R-Tenn.) said on NBC’s “Meet the Press.”

“At the end of the day I think people understand that if this is a bad deal that is going to allow Iran to get a nuclear weapon, they would own this deal if they voted for it, and so they’ll want to disapprove it,” he said.

“Likely, Iran will cheat by inches,” he added. “They will just cheat, cheat, cheat. And, over time, it’s like boiling an egg. They end up with a nuclear weapon.”

Obama has come under criticism from members of Congress and even some U.S. allies in the Middle East who say the administration has conceded too much in the talks.

Even after a final agreement is reached, Congress will have 60 days to assess the deal, during which lawmakers could try to build a veto-proof majority behind new legislation that could impose new sanctions on Iran or prevent Obama from suspending existing ones — a possibility that Senate Majority Leader Mitch McConnell hinted at.

“This is going to be a very hard sell for the administration,” McConnell said on “Fox News Sunday,” responding to questions over whether Congress would approve the deal.

“I know there will be a strong pull not to go against the president on something that is so important to him,” he added. “But it is a very hard sell.”