Talks on Iran's nuclear programme have entered their "endgame", Germany's Foreign Minister Frank-Walter Steinmeier has said.

Negotiators from six world powers are attempting to strike a deal with Iran to restrict its nuclear programme in exchange for sanctions relief.
The parties have set a deadline of the end of March to reach an agreement.

But some of the most contentious issues remain unresolved, says the BBC's Barbara Plett Usher.
"These are decisive days before us after nearly 12 years of negotiations with Iran," said Mr Steinmeier, as he arrived in the Swiss city of Lausanne for the talks.
"The endgame of the long negotiations has begun."

His French counterpart, Laurent Fabius, said: "We have made progress on some issues, but on some others we haven't made enough."
US Secretary of State John Kerry has already met Iranian Foreign Minister Mohammad Javad in Lausanne. Britain, China and Russia are expected to join them over the weekend, with comprehensive talks due Sunday.
They have set themselves a deadlines of 31 March for a political framework agreement and 30 June for a final deal.
Iran insists its nuclear programme is for peaceful purposes but world powers fear it has military ambitions.
Sticking points in the nuclear talks are thought to include the pace at which sanctions would be lifted, how long the deal will last and how much of Iran's nuclear facilities will be open to inspection.