Vienna: Russia, the United States and other world powers put their sharp differences over Ukraine to one side on Tuesday as they held their latest nuclear talks with Iran in Vienna.
The gathering is the second in a series of meetings aiming to transform by July a November interim deal into a lasting accord that resolves for good the decade-old standoff and removes the threat of war.
So far, despite disagreements over the Syria conflict and other issues, the six powers have shown a united front over Iran, but events in Ukraine in recent weeks have precipitated the worst crisis in East-West relations since the Cold War.
Following Sunday`s secession referendum in Crimea -- slammed as a sham by the White House and the European Union -- Brussels and Washington yesterday issued sanctions against a handful of Russian officials.
Today Russian President Vladimir Putin signed a treaty claiming Crimea as Russian territory and said the Black Sea peninsula has always been "in the hearts" of his compatriots.
Despite the tensions, a spokesman for Catherine Ashton, the powers` chief negotiator and EU foreign policy chief, said he had seen "no negative effect" on the Iran talks, with the six "still united".
But Mark Fitzpatrick, a former US State Department official now at the London-based International Institute for Strategic Studies, said the unfolding crisis made him "even more pessimistic".
"The Russians will... Be less likely to make sacrifices for the sake of unity over the Iran issues," Fitzpatrick told AFP. The Iranians, he said, "now have more reason to wait out the six powers".
