Foreign ministers from world powers have been invited to Vienna to evaluate nuclear talks underway with Iran, a spokesman for lead negotiator Catherine Ashton said on Thursday.
EU foreign policy chief Ashton "has invited ... foreign ministers who are available to come to Vienna on Sunday to take stock of where we are" in the talks, spokesman Michael Mann tweeted.
The talks between Iran and the five permanent members of the UN Security Council plus Germany, which began last week, are aimed at forging a lasting deal with Iran, meant to ease fears that the Islamic state might develop nuclear weapons.
The deadline to get a deal is July 20, when an interim deal struck by foreign ministers in Geneva on November 24 expires, although this can be extended if both sides agree to do so.
Earlier, a diplomat in Paris told AFP that French Foreign Minister Laurent Fabius would arrive on Sunday.
Rumours and reports in the Austrian capital also suggested US Secretary of State John Kerry and others would come too.
France has described the negotiations as "difficult" saying no major issues had been resolved, although Russia has said there were "clear signs of progress".
