U.S. mortgage activity fell slightly last week as long term interest rates were mixed, the Mortgage Bankers Association said Wednesday. In the week that ended Friday, U.S. mortgage activity fell 4.2 percent and refinancing fell 5 percent, the MBA said. Interest rates for 30-year, fixed-rate conforming mortgages rose from 3.56 percent to 3.57 percent with points rising from 0.4 to 0.42. The average interest rate for 30-year contracts on jumbo loans -- loans larger than $417,500 -- rose from 3.74 percent to 3.81 percent, a low for the history of the survey. Points for 30-year jumbo loans rose from 0.4 to 0.42. Interest rates for 15-year, fixed-rate mortgages dropped from 2.88 percent to 2.87 percent, falling for the eighth consecutive week and reaching a record low. Points for 15-year, fixed rate contracts fell from 0.4 to 0.39. The average rate for 30-year loans backed by the Federal Housing Administration was unchanged in the week, holding at an historic low of 3.34 percent, while the average rate for short-term adjustable rate mortgages fell from 2.6 percent to 2.59 percent in the week, the MBA said.