In his statements to the media, Jalili said the six-nation diplomatic bloc had not requested the closure of Fordo in Almaty.

"There is no justification for its closure, and they did not ask so," Jalili said, speaking through an interpreter.

Western diplomats were careful to characterize this week's talks as "useful."

And at least one longtime observer of Iran and its nuclear program said the latest meeting appeared to have produced some positive results.

"What is new in these Almaty talks are the positive reactions from Iran to the P5+1 proposal and what appear to be substantial adjustments of the P5+1 proposal itself," said Scott Peterson, author of a recently published book on Iran titled "Let the Swords Encircle Me."

Peterson said the apparent changes in the proposal "allow Iran -- at least at this stage -- to continue with its nuclear program, but in a more restricted way."