The first round of talks aimed at pushing forward a final deal on Iran's nuclear program has ended in Vienna.
Diplomats said the three-day round ending on April 24 focused on the pace of lifting international sanctions.
"The progress is good. We are at preliminary stages and the pace is slow but it is good," Iranian state television quoted Tehran's chief negotiator Abbas Araghchi as telling reporters.
On April 2, Iran and the so-called P5+1 group -- the United States, Russia, China, Britain, France, and Germany -- reached a framework deal that would curb Iran's nuclear activities, allaying Western fears it could develop an atomic bomb, in return for relief from sanctions.
Complicated details on timing and monitoring remain to be ironed out by a June 30 deadline set for a final deal.
Iran, which denies seeking nuclear weapons, has said sanctions must be lifted as soon as any final agreement is signed, while the United States wants a gradual lifting of restrictions.