GENEVA (AP) – Tehran on Saturday ruled out freezing its enrichment program, casting doubt over the sense of key nuclear talks between Iran and six world powers less than an hour after they began.

The talks – with the U.S. in attendance for the first time – had raised expectations of possible compromise on a formula that would have had Iran agree to stop expanding its enrichment activities. In exchange, the six powers, including the five permanent United Nations Security Council members, would hold off on passing new U.N. sanctions against the Islamic Republic.

But the comments from Keyvan Imani, a member of the Iranian delegation, appeared to indicate that Tehran was not prepared to budge on enrichment – at least going into the talks.

"Suspension – there is no chance for that," he told reporters gathered in the courtyard of Geneva’s ornate City Hall, the venue of the negotiations.