The Mortgage Bankers Association said U.S. mortgage activity rose slightly in the week ended Friday with long-term mortgage interest rates higher. Interest rates for 30-year, fixed-rate mortgages rose in the week from 4.18 percent to 4.25 percent with points rising from 0.44 to 0.47, the trade group said. Rates for 15-year, fixed-rate contracts rose from 3.49 percent to 3.53 percent with points unchanged at 0.45, the association said. The banking group said its weekly mortgage activity index and the refinancing index each rose 1.3 percent.