U.S. President-elect Barack Obama said on Saturday that he was crafting an aggressive, two-year stimulus plan to revive the troubled economy, warning that swift action was needed to prevent a deep slump and a spiral of falling prices. "If we don't act swiftly and boldly, most experts now believe that we could lose millions of jobs next year," Obama said in prepared remarks for the weekly Democratic radio and video address, quoted by Reuters. "We now risk falling into a deflationary spiral that could increase our massive debt even further," he said.