(CNN) — The heads of Iran’s nuclear negotiating team had a candid but welcoming exchange with the incoming U.S. secretary of state during a high-level meeting Friday to give the sides a preview of John Kerry’s plans for the delicate task of uniting the world against the Islamic Republic.
The agreement to meet each week in Vienna — in readiness for a June 30 deadline for a final deal with Iran — came amid renewed skepticism among experts about whether a final deal can be struck without an Iranian breakout period.
The meeting between Iran’s foreign minister and Kerry was part of an ongoing review of the April 2 agreement to limit Iran’s nuclear program in exchange for a phased lifting of economic sanctions.
It ended with the Obama administration welcoming Iran to formal talks.
“The United States will not impose greater restrictions on Iran’s nuclear program if Iran does not violate its international commitments. This remains the administration’s policy,” U.S. Deputy National Security Adviser Ben Rhodes said after the meeting.
But Iran, in a statement issued minutes later, said Kerry pledged Washington would continue to impose further economic sanctions on Iran to punish it for “violating international resolutions.”
The meeting in Vienna began after earlier tete-a-tetes by top Iranian and U.S. officials, including Foreign Minister Mohammad Javad Zarif, who met with Kerry Wednesday in Washington.
Six other world powers — Britain, China, France, Germany, Russia and the United States — as well as Iran are also involved in the talks.
Still, these countries, which represent nearly 100 countries, will have a harder time agreeing on the technical details because differences are not just technical. Iran has previously insisted that any deal must adhere to its “right” to nuclear technology for peaceful purposes.
While diplomatic talks moved ahead, tensions have mounted over the issue of Iran’s nuclear program.
Iran claims its civilian nuclear energy program has its sole intention to produce electricity. Israel, the U.S. closest military ally in the Middle East, is one of the foremost critics of the Iran nuclear talks and has called for the stoppage of the negotiations.
In addition, Iran also wants sanctions dropped, but some countries worry it will use its burgeoning economy to buy up neighboring countries and develop ballistic missiles.
In the past several weeks, the U.S. State Department sought to reassure allies in the Gulf that the talks were not a ploy to weaken Iranian influence in the region.
“There’s no question that what we have is a powerful consensus. … The question is whether it is strong enough to assert itself,” Kerry said in May.
Iran’s chief nuclear negotiator, Ali Akbar Salehi, said Friday it’s too early to know whether a deal will be reached.
“I believe it is possible for us to reach a settlement, and we believe the absence of any specter of war is going to be the guiding factor,” he said.
But a former U.S. official told CNN that it’s unlikely Iran will continue to talk if it does not reach an agreement.
“If they see no effort, they will walk away,” said Shahram Chubin, now with the Carnegie Endowment for International Peace.
If a deal is reached, experts say Tehran would be capable of producing enough highly enriched uranium to create between two and eight bombs in a matter of months.
Iran has confirmed it has complied with some U.N. Security Council resolutions against its nuclear program since the preliminary April accord.
But details of Iran’s compliance with the Nuclear Nonproliferation Treaty, which expires next year, remain unclear. Some countries are concerned that Iran has misled U.N. inspectors and has a secret stockpile of highly enriched uranium.