EU Deputy Secretary General Helga Schmid, Vice President of the European Commission Catherine Margaret Ashton, Iranian Foreign Minister Javad Mohammad Zarif, and Iranian ambassador to Austria Hassan Tajik attend the socalled EU 5+1 Talks with Iran at the UN headquarters in Vienna, on 8 April 2014. Picture: AFP.

Iran, 6 powers face 'gaps' in nuke talks

The overarching goal is to persuade Iran to scale back its nuclear programme.