By Paul Richter, Tribune Washington Bureau (TNS)

LAUSANNE, Switzerland — Marathon talks have produced the “key parameters” of a historic nuclear deal with Iran, officials said Thursday.

Officials said Iran agreed to a series of steps to sharply lower the threat that it could produce enough enriched uranium, or produce plutonium, as fuel for nuclear weapons for ten to fifteen years.

The International Atomic Energy Agency, the United Nations nuclear watchdog, would have regular access to all of Iran’s nuclear facilities in a regime of intense monitoring and inspections.

Most U.S. related sanctions would remain for the duration of the deal, but United Nations sanctions would be lifted more quickly if it complies with its obligations.

President Barack Obama, speaking in the Rose Garden, hailed what he called a “historic understanding with Iran” that if fully implemented, “will prevent Iran from obtaining a nuclear weapon.”

“It is a good deal, a deal that meets our core objectives,” Obama said.

Obama said that even if Iran cheats, the arrangement extends the time it would need to develop a bomb from two or three months to at least a year, giving the outside world time to intervene.

“This deal is not based on trust,” Obama said. “It’s based on unprecedented verification.”

The preliminary accord, the officials said, sets the stage for an additional three months of international diplomacy aimed at a forging an agreement to ease economic sanctions on Iran in exchange for limits on its ability to build a nuclear weapon.

The officials made the announcement after an all-night negotiating session and eight days of intense talks in Lausanne, Switzerland, between Iran and six world powers.
—
Earlier in the day, as talks between Iran and six world powers entered their eighth straight day, Foreign Minister Mohammad Javad Zarif said the diplomats had narrowed their differences in overnight wrangling between Secretary of State John F. Kerry, the Iranian team and European officials.

In a potentially positive sign, French Foreign Minister Laurent Fabius returned to this lakeside city late Wednesday, and German Foreign Minister Frank-Walter Steinmeier canceled a trip to the Baltic region that had been delayed to remain at the negotiations. If there is an announcement of a deal Thursday, at least some of the foreign ministers would want to be present.

The diplomats are seeking a preliminary outline of a deal that would ease sanctions on Iran if it accepts restrictions aimed at preventing it from obtaining a nuclear weapon. If they complete the first-stage agreement here, they hope to fill in all details of a comprehensive deal by June 30.

“We are moving,” Zarif declared earlier Thursday, as he emerged from long hours of talks just before 6 a.m.

Marie Harf, Kerry’s spokeswoman, said on Twitter that the session was “truly an all-nighter.” After more than eight hours of talks, the diplomats broke for about three hours of sleep, then resumed their meetings.

Diplomats cautioned that the talks, which have veered between optimism and gloom all week, could again stall. The negotiations have been slowed by differences between the six powers and Iran, and differences among the world powers.

Fabius, returning from Paris on Wednesday night, said negotiators remained “a few yards” from the finish line.

The Obama administration is under enormous pressure to demonstrate progress in the 18-month-old talks before Congress returns April 14 from a break. Skeptical lawmakers say that unless they see proof of progress, they will seek votes on two measures the administration believes could sink the talks.

Kerry still has two weeks to nail down the preliminary deal. But it may be easier to try to solve differences now than to try to bring diplomats back to Switzerland next week.

The White House, in an acknowledgment that the talks were skirting the edge of collapse, said Wednesday that Obama was prepared to take a new approach if progress was not possible.

Josh Earnest, the White House press secretary, said that while U.S. officials still see signs of progress, “if we are in a situation where we sense that the talks have stalled, then…the U.S. and the international community is prepared to walk away.”

But for the administration, the challenge is not just to get an agreement, but to reach one that demonstrates that the two sides are resolving the big issues that stand between them.

Administration officials have promised that they would explain to the public the decisions they have made. Earnest has said U.S. officials would describe how they intend to deal with dangers presented by the major Iranian nuclear sites.

But it appears likely that key issues, such as the handling of Iran’s stockpile of low-enriched uranium, will remain unresolved as the negotiations enter their final months.

Some analysts — including former members of Obama’s team — have said they are concerned that the deal could be less than advertised. That would further complicate the administration’s struggle to sell the deal to Congress and allies, when it is already under fire from critics.

Kerry is fabled for his dogged approach to diplomacy. During his last attempt to work out a peace deal between Israelis and Palestinians, Israeli officials joked ruefully about Kerry’s habit of showing up and simply waiting in hopes of wearing down the other side.

This may not be an auspicious week for a deal. A deal signed Wednesday might have been derided as the April Fool’s agreement. And Thursday is the 13th day of the Iranian new year, Zeizdah Bedar, considered an unlucky day for Iranians.

Photo: Olivier Douliery via TNS