Mogherini to attend Iran talks on Sunday: diplomatic source

(BRUSSELS) - The EU's foreign policy chief Federica Mogherini will join the Iran nuclear talks in Switzerland this weekend, a European diplomatic source said on Friday, two days before a key deadline.

"She is expected in Lausanne on Sunday," the European source said. French Foreign Minister Laurent Fabius and British Foreign Secretary Philip Hammond have also indicated that they will be present.

Hammond, on a visit to Washington, earlier said he would only fly to Switzerland if there was an immediate prospect of progress.

Hammond noted that a previous round of talks held in Vienna last November failed, and said he was now wary of "going and sitting in a hotel room for two days."

Earlier, a spokesman for French Foreign Minister Laurent Fabius, who has warned against a soft deal leaving Iran within reach of obtaining nuclear weapons, said he would join the talks on Saturday.

Fabius -- and Hammond if he decides to fly -- will join US Secretary of State John Kerry and his Iranian counterpart Mohammad Javad Zarif in Lausanne

After 18 months of intense negotiations, the fresh round of talks is aimed at reaching a deal before a final deadline of March 31.

The EU has helped mediate negotiations between the five UN permanent Security Council members -- Britain, China, France, Russia and the United States -- plus Germany and Iran.

The talks began in late 2013 after Iran accepted initial limits on its nuclear programme in return for an easing of some of the damaging economic sanctions imposed by the West.

The negotiations have been extended twice but all sides insist this will be the last round.

Iran insists its nuclear program is for civilian purposes, and wants its opponents to dismantle a complex web of economic sanctions that threatens to wreck its economy.