World

Iran nuclear talks: Envoys to discuss speed of sanctions relief, inspections of military sites

  • FILE In this April 27, 2015 file-pool photo, Secretary of State John Kerry meets with Iran's Foreign Minister Mohammad Javad Zarif  in New York. A month out from a nuclear deal deadline, the top U.S. and Iranian diplomats are gathering in Geneva this weekend, hoping to bridge differences over how quickly to ease economic sanctions on Tehran and how significantly the Iranians must open up military facilities to international inspections. Kerry and Zarif will meet Saturday. (AP Photo/Jason DeCrow, File-Pool)

    FILE In this April 27, 2015 file-pool photo, Secretary of State John Kerry meets with Iran's Foreign Minister Mohammad Javad Zarif in New York. A month out from a nuclear deal deadline, the top U.S. and Iranian diplomats are gathering in Geneva this weekend, hoping to bridge differences over how quickly to ease economic sanctions on Tehran and how significantly the Iranians must open up military facilities to international inspections. Kerry and Zarif will meet Saturday. (AP Photo/Jason DeCrow, File-Pool)  (The Associated Press)

  • U.S. Secretary of State John Kerry, right, speaks with Iranian Foreign Minister Mohammad Javad Zarif, left,  prior to a bilateral meeting for a new round of Nuclear Talks with Iran  at the Intercontinental Hotel, in Geneva, Switzerland, Saturday, May 30, 2015. A month out from a nuclear deal deadline, the top U.S. and Iranian diplomats gathered in Geneva Saturday in an effort to bridge differences over how quickly to ease economic sanctions on Tehran and how significantly the Iranians must open up military facilities to international inspections. (Laurent Gillieron/Keystone via AP)

    U.S. Secretary of State John Kerry, right, speaks with Iranian Foreign Minister Mohammad Javad Zarif, left, prior to a bilateral meeting for a new round of Nuclear Talks with Iran at the Intercontinental Hotel, in Geneva, Switzerland, Saturday, May 30, 2015. A month out from a nuclear deal deadline, the top U.S. and Iranian diplomats gathered in Geneva Saturday in an effort to bridge differences over how quickly to ease economic sanctions on Tehran and how significantly the Iranians must open up military facilities to international inspections. (Laurent Gillieron/Keystone via AP)  (The Associated Press)

  • U.S. Secretary of State John Kerry, left, talks with Iranian Foreign Minister Mohammad Javad Zarif, in Geneva, Switzerland, Saturday, May 30, 2015.  Top U.S. and Iranian diplomats are gathering in Geneva this weekend, hoping to bridge differences over a nuclear inspection accord and economic sanctions on Tehran. (AP Photo/Susan Walsh, Pool)

    U.S. Secretary of State John Kerry, left, talks with Iranian Foreign Minister Mohammad Javad Zarif, in Geneva, Switzerland, Saturday, May 30, 2015. Top U.S. and Iranian diplomats are gathering in Geneva this weekend, hoping to bridge differences over a nuclear inspection accord and economic sanctions on Tehran. (AP Photo/Susan Walsh, Pool)  (The Associated Press)

A month out from a nuclear deal deadline, the top U.S. and Iranian diplomats are gathering in Geneva this weekend, hoping to bridge differences over how quickly to ease economic sanctions on Tehran and how significantly the Iranians must open up military facilities to international inspections.

U.S. Secretary of State John Kerry and Iranian Foreign Minister Mohammad Javad Zarif planned to meet Saturday, though their talks are likely to extend into Sunday. Officials are describing the negotiating round as the most substantive since world powers and Iran clinched a framework pact in April.

That agreement, however, left big questions unanswered, which weeks of subsequent technical discussions have done little to resolve.

World powers believe they have secured Iran's acquiescence to a combination of nuclear restrictions that would fulfill their biggest goal: keeping Iran at least a year away from bomb-making capability for at least a decade. But they are less clear about how they'll ensure Iran fully adheres to the accord.

Various Iranian officials, including Ayatollah Ali Khamenei, the supreme leader, have publicly vowed to limit access to or even block monitors from sensitive military sites and nuclear scientists suspected of previous involvement in covert nuclear weapons efforts.

The U.S. says such access must be guaranteed or there will be no final deal. A report Friday by the U.N. nuclear agency declared work essentially stalled on its multiyear probe of Iran's past activities.

The Iranians aren't fully satisfied, either.

The unresolved issues include the pace at which the United States and other countries will provide Iran relief from international sanctions — Tehran's biggest demand — and how to "snap back" punitive measures into place if the Iranians are caught cheating.

President Barack Obama has used the "snapback" mechanism as a main defense of the proposed pact from sharp criticism from Congress and some American allies.

And exactly how rapidly the sanctions on Iran's financial, oil and commercial sectors would come off in the first place lingers as a sore point between Washington and Tehran.

Speaking ahead of Kerry's talks with Zarif, senior State Department officials described Iranian transparency and access, and questions about sanctions, as the toughest matters remaining.

They cited "difficult weeks" since the April 2 framework reached in Lausanne, Switzerland, but said diplomats and technical experts are getting back on a "smooth path."

None of the officials were authorized to be quoted by name and they demanded anonymity. They stressed that the U.S. was committed to completing the comprehensive agreement by the end of June.

Iran insists it is solely interested in peaceful energy, medical and research purposes, though many governments around the world suspect it of harboring nuclear weapons ambitions. The U.S. estimates the Iranians are currently less than three months away from assembling enough nuclear material for a bomb if they chose to covertly develop one.

Joining Kerry and Zarif in Switzerland will be U.S. Energy Secretary Ernest Moniz. American nuclear negotiator Wendy Sherman and her Iranian counterpart Abbas Araghchi are attending, too.