Update at 11:59 p.m. ET
U.S. Secretary of State John Kerry is returning to Washington today to brief President Obama on talks with Iran about its nuclear program, and about the possible need to extend negotiations past a July 20 deadline.
NPR's Peter Kenyon, who is reporting on the talks from Vienna, says that with just five days to go, Iranian Foreign Minister Mohammad Javad Zarif was showing some flexibility with Kerry and the foreign ministers of Britain, France and Germany.
Kerry told reporters in Vienna: "There has been tangible progress on key issues. However, there are very real gaps on other key issues."
He said he would consult with Obama about the prospects for a comprehensive agreement with Iran, "as well as a path forward" if no agreement is reached by July 20.
Zarif later told a news conference Iran insists "on having a serious, transparent and internationally monitored, peaceful nuclear program including serious and not symbolic enrichment." He added that serious enrichment means enough to fuel the Bushehr reactor after Russia's contract to supply fuel runs out in 2021.
NPR's Kenyon tells us that Zarif "also argued that it's not only the international community that needs reassuring, especially on the subject of nuclear fuel. He said it's naive to ask Iran to rely on outside fuel suppliers permanently."
"It's important for both sides to recognize the fact that their is mutual distrust. You cannot expect Iran to trust the international market, because the international market has betrayed us," Zarif said. "Had it not been for the betrayal of the international market, we never would have needed to produce fuel."
Zarif earlier told The New York Times that Iran was willing to maintain its current level of uranium enrichment for several years a significant concession compared with past public statements from Iranian officials.
The Times notes:
"Mr. Zarif's decision to go public with what he called an 'innovative proposal' appeared motivated to achieve two goals: to make it harder for the White House to walk away from a deal that would establish intrusive inspections and freeze Iran's program, but also to offer just enough for both sides to propose extending the talks beyond Sunday, the current deadline."
But the Iranian proposal does not address a major U.S. concern, the Times points out: It would leave Iran's centrifuges spinning in place, giving the Islamic republic "breakout capability" to make a nuclear bomb if it decided it wanted one.
The Associated Press reports that the main dispute over the two sides is over Iran's nuclear enrichment program.
"Tehran says it needs to expand enrichment to make reactor fuel, but the U.S. fears Tehran could steer the activity toward manufacturing the core of nuclear missiles," the AP reports. "The U.S. wants deep enrichment cut for at least 20 years; Iran wants to greatly expand enrichment over less than a decade."
Any potential deal faces skepticism from the U.S. Congress as well as from hard-liners in Iran.