Nuclear talks between Iran and its negotiating partners have made "significant progress", but there is no "final result yet", Iranian Foreign Minister Mohammad Javad Zarif has said.
The six powers - including the United States, Britain, France, Germany, Russia and China - "have to examine among themselves the results of the negotiations," Zarif said on Thursday. "We don't know yet the result of those discussions."
"What we expect today is a statement and the fact that we have all reached common understanding on how to resolve the issues," he added. "But the written agreement is something that needs to be drafted by all participants and agreed upon in a multilateral process."
The talks in Lausanne, Switzerland. are aimed at agreeing the outlines of a major deal to be finalised by June 30 to ease concerns that Iran might develop nuclear weapons under the guise of civilian programme, an aim it denies. Tehran wants to lift international sanctions that have crippled its economy, while preserving what it views as its right to nuclear technology for peaceful purposes.
Al Jazeera's James Bays, reporting from Lausanne, said: "The big question is what they come up with [after these meetings]. Is it going to be a framework agreement or a joint statement on common understanding of principles?"
He said a framework agreement would give the Obama administration a chance to persuade the US Congress not to introduce more sanctions on Iran, since .
Everybody taking part in the nuclear talks "think that if there are new sanctions, they will destroy the whole process," he said.
All sides are under pressure not to go home empty handed, but Washington reiterated on Wednesday that it was willing to walk away if the sides could not agree on a preliminary framework. White House spokesman Josh Earnest told reporters in Washington: "The time has come for Iran to make some decisions."
There were also signs that President Barack Obama, whose administration was behind the end-March interim deadline that was criticised by the French and others as an artificial one, was coming under renewed pressure from US Republican party leaders to walk away from the negotiations.
The negotiations have become bogged down over crucial details of the accord, even as the broad outlines of an agreement have been reached.
Negotiators met until 6am (04:00 GMT) on Thursday, breaking off for three hours to rest.
Ministers and experts shuffled from meeting to meeting overnight as talks entered their eighth day.
US Secretary of State John Kerry held meetings throughout the night with his Iranian, German and French counterparts, and European Union negotiator Helga Schmid.
Kerry and German Foreign Minister Frank-Walter Steinmeier said they would stay at least until Thursday in an effort to seal the agreement, a milestone towards a final pact due by the end of June. A German delegation source said Steinmeier would delay a trip to Estonia, Latvia and Lithuania.
Zarif said that the "real task" of hammering out this highly technical and complex final accord in the next three months will be a "difficult and immense task".
Source: Al Jazeera and agencies