"In previous rounds of talks, the Europeans were not very serious. Therefore, we were heavily critical, and this time the European side was more serious," Hossein Moussavian told state television.

"That's why we consider the negotiations process more positive."

"Both sides have begun practical talks, but there are still considerable differences between what we are demanding and the European position," he added.

"The Iranian delegation made it known to the Europeans that if the talks proceed with the same seriousness, cooperation is likely to continue beyond the initial three months."

Tehran insists its talks with the European Union, represented by Britain, France and Germany, and which began in mid-December, must have concrete results within three months if they are to continue.

On Friday, diplomats said EU negotiators had offered to send a mission to help Iran obtain a nuclear light-water research reactor, in what would be the first concrete move towards rewarding Tehran for abandoning uranium enrichment.

A light-water research reactor is less of a proliferation risk than a heavy-water reactor the Iranians want to build.

Britain, France and Germany are trying to convince Iran to dismantle an enrichment program the United States says is part of a covert atomic weapons development, in return for economic and political rewards.

Iran insists that its nuclear program is for purely civil purposes.

The United States is warily watching the talks, which wound up on Friday and are set to continue next month, apparently in Geneva.

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