A senior American diplomat chastised Iran on Saturday for vowing to press ahead with enriching uranium and producing nuclear fuel in defiance of US-led efforts to get it to stop. Gregory L. Schulte, the chief US representative to the Vienna-based International Atomic Energy Agency, called it "sad and ironic" that Tehran's announcement coincided with IAEA chief Mohamed ElBaradei's acceptance in Oslo, Norway, of the 2005 Nobel Peace Prize. He congratulated ElBaradei and the IAEA, which jointly won this year's Nobel, and said Washington "agrees that multinational cooperation is essential to counter this global threat." Iran has been under intense pressure to curb its nuclear program, which the United States claims is part of an effort to produce weapons. Iran says its program is aimed at generating electricity. The IAEA has warned Iran that its nuclear program could be referred to the UN Security Council, which has the power to impose sanctions on the country.