Obama delivered the statement Thursday.

Obama delivered the statement Thursday. Susan Walsh/AP

Obama on New Iran Agreement: 'It Is a Good Deal'

Negotiators settled on “key parameters” for a future deal on Thursday, three days past a self-imposed deadline.

The United States, Iran, and five other nations have reached a framework agreement for a final nuclear deal this summer.

Negotiators announced Thursday afternoon that the world powers "have reached solutions on key parameters on a joint comprehensive plan of action." Up next: drafting the deal, which would curb Iran's nuclear program in exchange for relief from some sanctions, before the official deadline at the end of June.

"This has been a long time coming," President Obama said during a statement this afternoon, calling the agreement "historic."

The framework agreement comes after marathon negotiations in Switzerland, which blew past a self-imposed deadline on Tuesday. Officials of the European Union and Iran announced the agreement during a joint statement Thursday afternoon in Switzerland.

"Today, after many months of tough, principled diplomacy, we have achieved the framework for [a] deal," Obama said Thursday. "And it is a good deal."

If Iran does not adhere to the final deal's requirements, Obama said, there will be consequences, like the return of sanctions, some of which would be lifted by the accord. "If Iran cheats, the world will know it," he said. "If we see something suspicious, we'll inspect it."

Obama acknowledged friction between his administration and Israeli Prime Minister Benjamin Netanyahu over the handling of negotiations. "It's no secret the Israeli prime minister and I don't agree about whether the United States should move forward with a peaceful resolution to the Iranian issue," he said. "If, in fact, Netanyahu is looking for the most effective way to ensure Iran doesn't get a nuclear weapon, this is the best option." Obama said he will speak with Netanyahu later Thursday.

The president offered a warning to members of Congress, some of whom—specifically Senate Republicans—the White House has accused of interfering with ongoing talks.

"If Congress kills this deal, not based on expert analysis and without offering any reasonable alternative, then it's the United States that will be blamed for failure of diplomacy," he said.

Secretary of State John Kerry, who has been engaged in marathon talks in Switzerland this week, praised the president during a statement Thursday afternoon. "I particularly want to thank President Obama. He has been courageous and determined in his pursuit of diplomatic path," he said. "From the day that he took office, President Obama has been crystal clear that a nuclear-armed Iran would pose a threat to our security and the security of our allies in the region, including Israel."

According to a State Department fact sheet, Iran has agreed to reduce the number of its installed centrifuges by approximately two-thirds, and any remaining ones will not be used for uranium enrichment. It has also agreed to decrease its uranium stockpile for 15 years, a process supervised by the International Atomic Energy Agency.

The country's Fordow facility—a source of contention during the talks—will be converted into a "nuclear, physics, technology, research center" to be used for "peaceful purposes." The site was a sticking point during the talks as negotiators sought to limit Iran's uranium enrichment levels.

The International Atomic Agency will also be tasked with monitoring the Natanz facility—the only site permitted to enrich uranium using its "first generation" centrifuges for 10 years.

When a final deal is reached, "nuclear-related economic and financial" sanctions imposed by the European Union will be lifted immediately, and the U.S. will grant relief from financial sanctions related to Iran's nuclear program.

If Iran does not abide by the deal's provisions, however, sanctions will "snap back into place," according to the State Department.

Back in Washington, Senate Minority Leader Harry Reid said in a statement that, after speaking with Obama about the agreement, he is "cautiously optimistic" about the framework. "Now is the time for thoughtful consideration, not rash action that could undermine the prospects for success," he said.

This morning, negotiators sounded hopeful ahead of the announcement. Javad Zarif, Iran's foreign minister, tweeted an optimistic message Thursday afternoon: "Found solutions. Ready to start drafting immediately."

"Big day: #EU , P5+1, and #Iran now have parameters to resolve major issues on nuclear program," Kerry tweeted . "Back to work soon on a final deal."

Iranian President Hassan Rouhani tweeted : "Solutions on key parameters of Iran #nuclear case reached. Drafting to start immediately, to finish by June 30th. #IranTalks."

The negotiations oscillated between productive and faltering this week. Foreign ministers of three of the six world powers left late Tuesday night. One returned less than 24 hours later. Kerry said Wednesday that he would be extending his stay.

Negotiations revolved around Iran's nuclear research and development capabilities, and the time and scope of sanctions removal. Iran had sought relief from sanctions imposed by the U.S. and other nations that have crippled its economy.

While the deadline for a concrete deal isn't until the end of June, this week's milestone was being closely watched in Washington. Congressional leadership had signaled it would move on legislation to impose additional sanctions against Iran "very quickly" if talks fell apart. The administration has also said repeatedly that no deal is better than a bad deal.

"If we are not able to reach a political agreement, we are not going to wait all the way to June 30 to walk away," Earnest said on Tuesday.