Average US rate on 30-year mortgage falls to 3.91 percent; 15-year rate down to 3.13 percent

Average long-term U.S. mortgage rates fell for a third straight week amid anxiety over developments in the U.S. economy that lifted bond prices.

Mortgage giant Freddie Mac says the average rate on a 30-year fixed-rate mortgage dipped to 3.91 percent this week from 3.98 percent a week earlier. The rate on 15-year fixed-rate mortgages declined to 3.13 percent from 3.17 percent.

Mortgage rates followed the yield on the key 10-year Treasury note, which fell. Bond yields for Treasurys were pushed lower by the increase in bond prices, as investors sought safety in U.S. Treasury bonds.

Investors are closely awaiting the government's report Friday on July employment, since the jobs data could affect the timing of an anticipated interest rate increase by the Federal Reserve.