In a rare show of unity, Iran and the world's big powers hailed their first nuclear meeting in more than a year as a key step towards further negotiations meant to ease international fears that Tehran may weaponise its nuclear programme.
The one concrete reflection of progress was an agreement to meet again on 23 May in Baghdad, a venue proposed by Iran.
Officials from the United States, Russia, China, Britain, France and Germany met with Iranian delegates in Istanbul to discuss the country's nuclear program. The EU's foreign policy chief, Baroness Ashton, who formally led the talks on behalf of the six powers, said they were "constructive and useful".
She expressed the hope they would lead to "a sustained process of serious dialogue, where we can take urgent practical steps to build confidence and lead on to compliance by Iran with all its international obligations".
The Iranian chief negotiator, Saeed Jalili, said the talks made "some progress" but that there were "some points of difference".