Russian and Iranian officials have ended two days of talks in Moscow about a proposal to resolve Iran's nuclear standoff with the West.
After Tuesday's session, the head of the Iranian delegation, Ali Hosseinitash, described the talks as "positive and constructive."
Both sides said further discussions will be held in Tehran. No date was announced.
The two sides were discussing a Russian proposal to allow Iran to enrich uranium on Russian soil for use in Iran's nuclear plants. The plan was aimed at easing Western concerns that Iran would use the process to produce bomb-making material. It was viewed as Iran's last chance to address the issue before a meeting on March 6 of the International Atomic Energy Agency.
The IAEA meeting could result in the U.N. Security Council taking up the question of Iran's activities, and possibly imposing sanctions or other penalties on Tehran.
Earlier this month, Iran restarted uranium enrichment, which could produce fuel for civilian nuclear reactors or material for weapons.
Western countries say Iran is secretly trying to develop nuclear weapons, a charge Iran denies.
Some information for this report was provided by AFP, AP and Reuters.