U.S. Secretary of State John Kerry met his Iranian counterpart for more than an hour on Sunday and stressed the need to make progress in nuclear negotiations this week on the sidelines of U.N. meetings.

Kerry and Iranian Foreign Minister Mohammad Javad Zarif also discussed the threat posed by Islamic State militants in Syria and Iraq, a senior State Department official said, without elaborating…

Tehran has sent mixed signals about its willingness to cooperate on tackling Islamic State, which has seized huge swaths of territory across Syria and Iraq.

Senior Iranian officials told Reuters that Iran was ready to work with the United States and its allies to stop Islamic State fighters but would like to see more flexibility on Iran’s uranium enrichment program.

Secretary of State John Kerry said Friday that Iran has a role to play in an international coalition to fight ISIS — just days after the Iranian president dismissed the U.S.-led coalition against the terror group as “ridiculous.” “The coalition required to eliminate ISIL is not only, or even primarily, military in nature,” Kerry said at a United Nations Security Council meeting on Iraq, using an alternative name for the radical Sunni militants. “It must be comprehensive and include close collaboration across multiple lines of effort. … There is a role for nearly every country in the world to play, including Iran.”…

The U.S. has previously signaled a reluctance to work with Iran to tackle the global threat of ISIS. America severed diplomatic ties with Tehran amid the tense hostage following the 1979 Islamic revolution. President Barack Obama has said 40 nations have pledged help to a coalition against the ISIS fighters.

Iran is ready to work with the United States and its allies to stop Islamic State militants, but would like more flexibility on Iran’s uranium enrichment program in exchange, senior Iranian officials told Reuters.

The comments from the officials, who asked not to be named, highlight how difficult it may be for the Western powers to keep the nuclear negotiations separate from other regional conflicts. Iran wields influence in the Syrian civil war and on the Iraqi government, which is fighting the advance of Islamic State fighters…

[Iranian] officials said they would like the United States and its Western allies to show flexibility on the number of atomic centrifuges Tehran could keep under any long-term deal that would lift sanctions in exchange for curbs on Tehran’s nuclear program.

“Both sides can show flexibility that will lead to an acceptable number for everyone,” another Iranian official said.

[In January], the Iranians were disinvited from the international conference in Switzerland, attended by nearly forty countries, on how to end the Syrian civil war. Tehran believed that it could help broker a new government, as it had for Afghanistan after the Taliban’s ouster, in 2001. Iran had a four-point plan, which included a ceasefire and democratic elections that would be monitored by the United Nations but would allow President Bashar al-Assad to campaign to keep his office. Other participants balked. The reasons reflected regional rivalries and sectarian tensions, and, more fundamentally, Iran’s designation as a state sponsor of terrorism by the State Department and its longstanding military ties to Assad. The Islamic Republic had credibility problems.

The diplomatic initiative, which brought together representatives of the Syrian government and Western-backed rebels, quickly fizzled, and ISIS gained ground against both the government and the moderate rebels. By June, black-hooded gunmen were racing their pickups across the Syrian border back into Iraq…

But Zarif’s main pitch in New York—which is likely to be a theme of President Rouhani’s appearance at the United Nations next week—is that any campaign to eradicate the ISIS forces can’t rely on mere aerial bombardment. He told the Council, “We also need to stop providing them with those recruiting grounds, with those fertile possibilities of resentment, of disenfranchisement that can allow them to attract the youth in so many parts of the world, from the Middle East to Europe and the United States.” Next time, it was clear, Iran doesn’t want to be excluded from the process.

Over the years, the United States has shown considerable ingenuity in its effort to slow Iran’s production of nuclear fuel: It has used sabotage, cyberattacks and creative economic sanctions.

Now, mixing face-saving diplomacy and innovative technology, negotiators are attempting a new approach, suggesting that the Iranians call in a plumber.

The idea is to convince the Iranians to take away many of the pipes that connect their nuclear centrifuges, the giant machines that are connected together in a maze that allows uranium fuel to move from one machine to another, getting enriched along the way. That way, the Iranians could claim they have not given in to Western demands that they eliminate all but a token number of their 19,000 machines, in which Iran has invested billions of dollars and tremendous national pride.

And if the plumbing is removed, experts at America’s national nuclear laboratories have told the Obama administration, the United States and its allies could accurately claim that they have extended the time Iran would need to produce enough fuel for a bomb — and given the West time to react…

“There’s a bit of a sense of desperation about coming up with ways to break the logjams, on the nuclear talks and the larger relationship,” another participant in the negotiations said. “Because if we don’t figure this out in the next few months, it is not clear the opportunity is going to come again.”

The Obama administration is frantically searching for “creative solutions” to get to a nuclear deal with Iran, but according to 31 Republican senators, the administration is getting way too lenient while trying to entice Tehran to get to yes…

The GOP senators want Kerry to say definitively whether he would accept disconnecting centrifuges and whether he would agree to other controversial concessions, like allowing the Arak heavy water reactor to continue functioning or signing a deal that expires in only a few years. Former Obama administration nuclear negotiator Bob Einhorn wrote that reactors like the one in Arak were “excellent plutonium bomb factories.”…

“The Iranians have said over these many days and weeks how reasonable and flexible they are in these talks, and about how their current capacity should be acceptable. But the status quo is not doable for any of us. It is not doable for either side,” the official said. “The world will agree to suspend and then lift sanctions only if Iran takes convincing and verifiable steps to show that its nuclear program is and will remain exclusively peaceful.”

Behind the scenes there’s a lot of concern that Iran may be just playing for time and not ready to make any real sacrifices, jeopardizing the negotiations and a pillar of what President Obama wants to be his foreign policy legacy, a new relationship with Iran.

With Khamenei’s health in question, longtime regime insiders appear to already be paving the way for him to be replaced with an equally extremist and hardline ruler who would enter the political fray at perhaps the most significant time in Iran’s history…

Iran’s most extremist elements are already believed to be plotting against the somewhat more moderate President Hassan Rouhani, who has made nuclear negotiations with the West among his top priorities…

“As if the [nuclear] negotiation itself was not enough of a problem for Rouhani, the U.S. move to support rebel forces in Syria that would fight both the Islamic State and Iran’s ally, the Assad regime, is a major problem for Tehran,” according to Stratfor.

“U.S. and Iranian interests overlapped with regard to the IS threat in Iraq,” it states. “But in Syria, the United States must rely on anti-Iranian actors to fight IS and the Obama administration seeks to topple the Assad regime Accordingly, less than a year after the two sides embarked upon a rapprochement, tensions seem to be returning.”