French Foreign Minister to Return to Vienna for Iran Talks

French Foreign Minister Laurent Fabius said Monday he plans to return to Vienna this week as world powers work to finalize a landmark deal on Iran's nuclear program.

"I will be back in Vienna this week," Fabius told reporters in New York where he was to attend a U.N. event on climate change.

Negotiators had set a June 30 deadline to agree on a final deal, but the talks were expected to go into overtime, though it remained unclear for how long.

"We agreed not to set a date," Fabius said of the new schedule of talks.

Iran and the P5+1 group -- Britain, China, France, Germany, Russia and the United States -- are seeking to flesh out the final details of an accord that would bar Tehran from acquiring a nuclear weapon in exchange for a lifting of sanctions.

One of the most contentious issues has been the sequence for easing sanctions and the so-called "snapback mechanism" by which sanctions would be re-imposed if Iran violates the terms of the deal.

"We have made some progress but still, it is not the end of the process," Fabius said.

"In particular, Iranians are asking precisions about lifting of sanctions -- What does it mean? How does it work? -- and we on the P5+1 side, we are asking for some precision," said Fabius.

The foreign minister restated that France wants "a good agreement, but this agreement has to be robust" to deter other countries in the "eruptive" Middle East from seeking a military nuclear capability.

France has taken a tough line on the Iran talks, demanding that Iran agree to inspections of its nuclear sites among other conditions for a deal. 

Fabius sidestepped questions on whether he was optimistic about prospects for the historic deal that would end a standoff with Iran dating back to 2002.