Fixed mortgage rates on long-term loans in the United States rose for the third consecutive week, the Federal Home Loan Mortgage Corp. said Thursday. After months of setting or flirting with record lows, \"the latest economic indicators point toward low inflation but gradually stronger economic activity which placed further upward pressure on long-term Treasury yields and, in turn, fixed mortgage rates,\" said Freddie Mac Chief Economist and Vice President Freddie Nothaft. For the week, the average 30-year fixed mortgage, which has been below 4 percent for every week but one in 2012, rose from 3.59 percent to 3.62 percent with an average 0.6 points, Freddie Mac said. A year earlier, interest rates for 30-year, fixed-rate loans were at 4.15 percent. For 15-year loans in the week ending Thursday, interest rates rose from 2.84 percent to 2.88 percent with an average 0.6 points. A year ago, 15-year loan rates averaged 3.36 percent. Interest rates for five-year adjustable-rate mortgages fell slightly from 2.77 percent to 2.76 percent in the week with 0.6 points. In the same week of 2011, rates for five-year ARM contracts stood at 3.08 percent. The average interest rates for one-year ARM contracts rose from 2.65 percent to 2.69 percent in the week with 0.4 points. Rates a year ago for one-year ARM contracts averaged 2.86 percent.