Iran Nuclear Talks Deadline Will Be Extended By A Day, U.S. Says

This post was last updated at 7:54 p.m. ET

The U.S. says enough progress has been made in talks with Iran on its nuclear program to warrant an extension of Tuesday's 6 p.m. ET deadline by a day.

"We've made enough progress in the last days to merit staying until Wednesday," spokeswoman Marie Harf said in a statement. "There are several difficult issues still remaining."

She said Secretary of State John Kerry, who was scheduled to leave the talks Tuesday, will remain until Wednesday.

In Washington, White House spokesman Josh Earnest said talks in Lausanne, Switzerland, "continue to be productive," but if there is no political agreement by the June 30 deadline for an agreement, "we would walk away from the negotiating table."

It's important to note here that the 6 p.m. Tuesday deadline is self-imposed. As The Washington Post explains: "When talks were extended in November, Kerry said that if the parties did not have a broad agreement by the end of March, Obama would have to reassess whether to continue the negotiations." But the June 30 date Earnest referred to is the deadline the U.S. and its allies in the talks — Britain, China, France, Germany and Russia — set with Iran over restrictions to its nuclear program.

Update at 7:54 p.m. ET. Conflicting Reports On Progress:

As negotiations came to a close in the early hours of Wednesday in Switzerland, there were conflicting reports about progress.

Russia's Foreign Minister Sergey Lavrov came out hopeful, saying, according to Russia Today, that "we can quite certainly say that on all the key aspects of the final settlement of this problem, the ministers have reached principal consent that will be, hopefully in the next hours, maybe a day, put on paper."

The French, which have driven a tough bargain in these negotiations, could not have come out with a more different statement.

French Foreign Ministry political director for Iranian affairs Nicolas de Riviere said there was still "much work to do."

And Reuters reports that France's Foreign Minister Laurent Fabius has left the talks in Switzerland, headed for France.

Quoting an official, Reuters reports that Fabius "will come back as soon as it's useful."

Our original post continues:

The six nations that have been debating a plan to curb Iran's nuclear program and ease economic sanctions will hit the deadline for a framework agreement at 6 p.m. ET. Ahead of that deadline, there are signs that a deal is in the works — and that it might not be a sweeping arrangement that lays out future terms.

Early Tuesday, Russian Foreign Minister Sergei Lavrov said he believed an agreement would be reached by the end of the day.

"Lavrov said the chances for a deal are high," NPR's Corey Flintoff reports from Moscow, "as long as none of the parties raises the stakes at the last minute."

The Associated Press reports that the parties involved are now preparing "to issue a general statement agreeing to continue talks." The news agency said that later Tuesday, we should expect to see a joint statement that announces a framework understanding.

At the meetings in Lausanne, Switzerland, diplomats from Iran, the U.S., Russia, France, Britain, China, and Germany have struggled to resolve key issues such as how and when sanctions on Iran could be lifted, as well as how Iran's existing nuclear stockpile should be stored.

Their goal has been to hammer out a framework arrangement on political terms. More technical and specific aspects would then be included in a separate round of talks, with a June deadline for a final agreement.