Lausanne: Marathon talks to draw up the outlines of a landmark Iran nuclear deal by a March 31 deadline looked set on Wednesday to go down to the wire as Tehran played down chances of finishing the job this week.
Iranian Foreign Minister Mohammad Javad Zarif, currently holding talks in Switzerland with US Secretary of State John Kerry, said other foreign ministers from world powers involved in the negotiations were unlikely to join them.
The arrival of the foreign ministers of Russia, China, Britain, France and Germany in Lausanne could indicate that a long-elusive deal might be at hand.
"I don't think their presence will be needed in this round," Zarif told Iranian state media from the Swiss lakeside city.
"When the solutions are found and we approach a deal, then all the foreign ministers of the negotiating parties should come," he said.
As a result the negotiations will likely have to continue into next week or resume then after a break.
Iran and the six powers have been seeking in months of talks to transform an interim deal struck in November 2013 into a lasting accord that they hope will convince the world that Iran is not about to develop nuclear weapons.
Such an agreement would involve Iran scaling down its nuclear activities to within strict limits in exchange for relief from painful sanctions after 12 years of rising tensions over its atomic programme.
Two earlier target dates last July and then again in November were missed, but experts say that the new deadline -- March 31 for a framework deal, July 1 for the full deal -- has to be met.