Iran nuclear talks 'constructive', says EU spokesman

Key talks on Iran's controversial nuclear programme, which have resumed after a 15-month impasse, have been described as "constructive".

Six world powers - the US, UK, France, China, Russia and Germany - and Iran are meeting in Istanbul in Turkey.

Iran says its nuclear programme is peaceful, but critics suspect it of seeking to develop nuclear weapons.

Michael Mann, the chief spokesman to the EU foreign policy head, Catherine Ashton, said the mood was "good".