Six world powers have failed so far to make any clear progress at talks with Iran on its nuclear program, Russian news agency Interfax quoted a source close to the talks as saying on Wednesday, Feb 27, according to Reuters.

"So far there is no particular rapprochement. There is an impression that the atmosphere (at talks) is not very good," the source said in the Kazakh city of Almaty where a second day of talks was under way.