Rice was speaking in Berlin following a breakfast meeting with the foreign ministers of Germany, Russia and EU foreign policy chief Javier Solana.
A U.N. nuclear watchdog report due later in the day is likely to confirm Iran has escalated rather than halted its nuclear fuel program, exposing Tehran to wider sanctions over fears it is secretly seeking atom bombs.
“We reconfirmed that we will use our available channels and the Security Council to try and achieve that goal,” Rice said, referring to the relaunch of talks.
Rice said the hope was that sanctions would show Iran that isolation would only increase over time.
She said western powers were awaiting the report from International Atomic Energy Agency (IAEA) director Mohamed ElBaradei before taking any specific action.
Iran has offered to guarantee that it is not pursuing nuclear weapons, but has refused to shelve its program as a precondition for talks with the United States, Russia, China, Britain, France and Germany on trade incentives.
“We remain hopeful that at some point they will want to take it up,” Rice said of an incentives package the world powers presented to Iran last June.
DIPLOMATIC SOLUTION?
British Prime Minister Tony Blair, speaking to BBC radio on Thursday, echoed Rice, saying a diplomatic solution to the standoff was the only one “anyone can think of”.
He said he was not aware of any plans to attack Iran over its nuclear program but when pressed repeatedly on whether an attack was inconceivable, Blair declined to say so.
Solana, speaking on German N24 television, said the door was still open to Iran on talks, adding: “I think no one is talking about military action.”
A 60-day grace period for Iran to stop enriching uranium expired on Wednesday. Its defiance of preconditions set for talks means the Security Council could weigh broadening the limited sanctions it imposed on Tehran in December.
Rice said last week it was likely that Washington would seek another Security Council sanctions resolution on Iran, the clearest indication so far by a senior U.S. official that the U.S. was seriously considering such a step.
“We are certainly exploring it and I think we probably think, at this point, it’s likely we would pursue one, but we haven’t made the decision,” Rice said in an interview with U.S. newspaper reporters last Thursday.
