Paris:
French Foreign Minister Laurent Fabius will travel to Vienna on Sunday to assess the state of talks between world powers and Iran over curbs on the Islamic republic's nuclear programme, a diplomatic source in Paris said.
Fabius and officials in the P51 group comprising the United States, Russia, Britain, France, Germany and China will "evaluate the situation" in the talks, which aim to reach a definitive accord with Iran by July 20, according to the source.
The source did not say which other foreign ministers would attend.
Final negotiations to secure a historic accord to guarantee the peaceful nature of Iran's nuclear programme in exchange for the lifting of sanctions against Tehran began on July 3 in Vienna.
The diplomatic marathon could continue until July 20 when a temporary deal struck agreed in November 2013 expires.
However, the deadline for this latest round could be extended for six months.
France has described the negotiations as "difficult" and on Tuesday said no major issues had been resolved.
EU foreign policy chief Catherine Ashton, who is leading the talks, said earlier this week she was considering asking foreign ministers to attend.
On Tuesday Iranian news agency IRNA reported that foreign ministers from the five permanent members of the UN Security Council would arrive in Vienna later this week.