LAUSANNE, Switzerland -- Nuclear talks between Iran and six world powers are expected to go on past a midnight deadline for the outline of an agreement.
Representatives meeting in the Swiss resort city of Lausanne have been negotiating a framework agreement to impose limits on Tehran's nuclear program in exchange for sanctions relief.
They are now reportedly preparing to issue a general statement focusing on points of agreement, which would allow the sides to continue negotiations until the June 30 final deadline for a comprehensive deal.
U.S. State Department spokeswoman Marie Harf said, "We've made enough progress in the last days to merit staying until Wednesday.”
"There are several difficult issues still remaining," she added.
Earlier, Russian Foreign Minister Sergei Lavrov said a draft framework agreement has been reached between Iran and six world powers that includes proposals to lift economic sanctions against Iran in exchange for curbs to its nuclear program.
But the claim has been denied by U.S. diplomats at the talks in Switzerland.
Saying that a final deal is “completely reachable,” Lavrov said experts would work out the remaining technical details in the weeks ahead with the aim of reaching a final nuclear agreement by the end of June.
Lavrov told TASS: "One can say with enough confidence that [foreign] ministers have reached a general agreement on all key aspects of a final settlement to this issue. It will be put down in writing over the next few hours, maybe during the day."
Despite Lavrov’s upbeat assessment, Reuters, AP, and AFP quoted unnamed U.S. diplomats close to the talks who said it was “not true” that an agreement had been reached on all key issues.
Obstacles that remained as foreign ministers from Iran and the six world powers and European foreign policy chief Federica Mogherini began a fresh round of talks just before midnight on March 31 included several main issues -- uranium enrichment, where stockpiles of enriched uranium should be stored, limits on Iran's nuclear research and development and the timing and scope of sanctions.
About two hours after the late night talks resumed, Iranian Foreign Minister Mohammad Javad Zarif emerged from the negotiations early on April 1 and told reporters that there had been “good progress.”
Zarif also said that he hoped for a “conclusion” on a framework political accord later on April 1.
French Foreign Minister Laurent Fabius, meanwhile, left the negotiations early on April 1, saying that he would return when it was “useful” and when he was needed.
In Washington, the White House announced that President Barack Obama held a video conference late on March 31 (Washington time) with U.S. Secretary of State John Kerry and other members of his national security team, including Vice President Joe Biden and Defense Secretary Ash Carter.
The White House said that video conference provided Obama with an update on the status of the negotiations in Switzerland.
The negotiations were extended into the early morning hours of April 1 after negotiators decided to ignore a self-imposed midnight deadline to reach the outline of a political agreement that would allow the talks to enter a new phase.
Iran Nuclear Talks Timeline: How We Got Here
The United States, Britain, France, China, and Russia plus Germany have been seeking verifiable curbs on Iran’s nuclear program that ensure Tehran is not able to develop a nuclear weapons capability.
Iran, which denies it is trying to build nuclear weapons, wants crippling economic sanctions to be lifted.