Vienna:
Iran and six world powers started a round of talks in Vienna on Tuesday, hoping to make progress in their years-old dispute over Tehran's nuclear intentions despite a crisis over Crimea that has fuelled tensions among the powers.
The powers - the United States, Russia, China, France, Britain and Germany - want Iran to curtail its nuclear programme to the point when they would feel secure it could not yield bombs.
Tehran, a major oil producer which says its nuclear programme is entirely peaceful, wants the West to lift economic sanctions, particularly against its oil and banking sectors.
The sides hope to have a deal done by the middle of July but diplomats are wary that a conflict between the West and Russia over Moscow's takeover of the Ukrainian region of Crimea could complicate the talks.
© Thomson Reuters 2014