France's foreign minister appeared to put pressure on the United States and Iran on Saturday to speed up nuclear talks, saying that all issues were now on the table between six major powers and Iran and that the time had to come to make a decision.
The two sides nevertheless struggled to break the deadlock in nuclear talks that has held up a historic deal that would bring sanctions relief for Tehran in exchange for curbs on its atomic program.
Tehran and the six powers have given themselves until Monday to reach a nuclear agreement, their third extension in two weeks, as the Iranian delegation accused the West of throwing up new stumbling blocks to a deal.
"Now that everything is on the table, the moment has come to decide," Laurent Fabius said in a statement sent to Reuters.
The statement came after Fabius had conversations with U.S. Secretary of State John Kerry, Iranian Foreign Minister Mohammad Javad Zarif and British Foreign Secretary Philip Hammond.
Among the biggest sticking points at the moment is Iran's insistence that a United Nations Security Council arms embargo and ban on its ballistic missile program dating from 2006 be lifted immediately if an agreement is reached.
Russia, which sells weapons to Iran, has been publicly supporting Tehran on this issue.
However, a senior Western diplomat said earlier in the week the six powers - the United States, Britain, Germany, France, Russia and China - remained united over the issue, despite Moscow's and Beijing's well-known dislike of the embargos.
Western powers have long suspected Iran of aiming to build nuclear bombs and using its civilian atomic energy program to cloak its intention - an accusation Iran strongly denies.
Other problematic issues in the talks are access for inspectors to military sites in Iran, answers from Tehran over past activity and the overall speed of sanctions relief.
"Still have difficult issues to resolve," Kerry tweeted on Saturday after meeting Zarif.
The two men have met nearly every day since Kerry arrived in Vienna more than two weeks ago for what was intended to be the final phase in a negotiation process lasting more than year and a half aimed at securing a long-term deal with Iran.
Kerry told reporters late on Friday the atmosphere in the talks was constructive.
"A couple of differences have been decided ... It's safe to say we have made progress," he said, without giving any details. Fabius and Hammond returned to Vienna on Saturday.
It remained unclear whether Russian Foreign Minister Sergei Lavrov would return on Saturday. The Russian foreign ministry told Reuters his travel plans had not been finalized.
The negotiations in the last few days have become bogged down, with diplomats speaking of a shouting match between Kerry and Zarif.
The White House said on Friday that the United States and its partners "have never been closer" to agreement with Iran but that the U.S. delegation would not wait indefinitely.
A senior Iranian official speaking on condition of anonymity said on Thursday the United States and other Western powers were shifting their positions and backtracking on an April 2 interim accord that was meant to lay the foundations for a final deal.
An agreement would be the biggest step towards rapprochement between Iran and the West since the 1979 Islamic Revolution, although both sides are likely to remain wary of each other even if a deal is concluded.
Iranian Supreme Leader Ayatollah Ali Khamenei told a meeting of students in Tehran on Saturday that the United States is the "true embodiment of global arrogance," according to remarks posted on his website.
Answering a student who asked him what would happen to the "fight against global arrogance" after the completion of nuclear talks between Iran and world powers, Khamenei replied that fight could not be interrupted, his website said.
Khamenei was quoted as saying: "Fighting global arrogance is the core of our revolution and we cannot put it on hold. Get ready to continue your fight against the global arrogance."
"The US is the true embodiment of the global arrogance."
(Reporting by Parisa Hafezi, Arshad Mohammed, Shadia Nasralla; Writing by Louis Charbonneau and John Irish; Editing by Hugh Lawson)