WASHINGTON (AP) — Average long-term U.S. mortgage rates slipped this week after they climbed recently expectations that the Federal Reserve may soon raise its key short-term interest rate. Foreign buyers poured into 10-year U.S. Treasury bonds in October, temporarily depressing mortgage rates that have since risen as the market focus has returned to the Fed. Some Fed policymakers have indicated that the 5 percent unemployment rate and potential for rising inflation levels merit a rate increase, signaling the end of extraordinary stimulus measures that began during the Great Recession.