Russia voiced confidence on Tuesday that world powers and Iran would be able to reach a comprehensive accord over Tehran's disputed nuclear programme by a June 30 final deadline.
Moscow's chief nuclear negotiator said after the latest round of talks between US Secretary of State John Kerry and Iranian Foreign Minister Mohammad Javad in Geneva that tangible progress was being made.
"We are satisfied to see every new meeting achieve further progress," the RIA Novosti news agency quoted Russia's Deputy Foreign Minister Sergei Ryabkov as saying.
"There is a growing confidence that an agreement will be reached by the assigned deadline -- in other words, June 30," Ryabkov said in the Swiss city.
Negotiators for Iran and six world powers have been meeting in Geneva since Friday in a bid to resolve the decade-long dispute. A senior US administration official said they intended to continue the talks next week.
Negotiators must by March 31 reach a political framework for a deal that could ease international concern about a possible military dimension to Iran's nuclear enrichment programme.
The technical details of that accord must then be hammered out by June 30 or the current sanctions against Tehran will remain in place and possibly be toughened.
Iran insists that its nuclear programme is for civilian use only and complies with international law.