The Istanbul nuclear talks held on Saturday between Iran and the six world powers were "constructive," the Russian Foreign Ministry said on Sunday.

"The meeting was held in a constructive and respectful atmosphere and demonstrated the parties' readiness to search for mutually acceptable negotiated solutions (to Iran's nuclear program)," the ministry said in a statement.

Also on Sunday, Deputy Foreign Minister Sergei Ryabkov, who attended the Istanbul talks as Russia's representative, told Itar-tass news agency that Moscow was satisfied with the results of the talks.

He confirmed the parties have reached consensus on several specific issues.

"The main thing is we have reached an understanding that we should go further on the principles of step by step and reciprocity, which Russia has defended from the outset of the present stage of dialogue with Iran," Ryabkov said.

The diplomat also confirmed that the parties will continue their talks in Baghdad on May 23.

"This is a good result, taking into account the fact that some 15 months elapsed between the previous and the present round," Ryabkov said.

The last round of talks were held in Istanbul in January last year, but no agreement was reached.

The six powers, including the United States, France, Russia, China, Britain and Germany, spearheaded the diplomatic efforts to persuade Iran to limit its nuclear program, which Iran say is purely peaceful while UN and Western leaders suspect of military purposes.