U.S. negotiators repeatedly shifted their goals during talks over Iran's nuclear program in response to intransigence from Tehran's representatives, according to a published report. Meanwhile, France's top diplomat urged caution Friday about the possibility of a final deal being agreed to and admitted that his country had initially held out for firmer terms. Diplomats representing the so-called P5+1 powers and Iran announced that they had a framework of an agreement Thursday after marathon talks in Switzerland that stretched two days past their original deadline.