WASHINGTON — Mortgage rates fell sharply this week with rates on 30-year mortgages dropping to the lowest level in more than two years.

Freddie Mac, the mortgage company, reported yesterday that 30-year fixed-rate mortgages averaged 6.10 percent. That was down from 6.20 percent last week and was the lowest rate since the week of Oct. 13, 2005, when rates stood at 6.03 percent.

Analysts attributed the decline to increased worries that a severe slump in housing and a continuing credit crunch could drag the economy into a recession. The recent turbulence in the stock market has prompted many investors to rush to the safety of U.S. Treasury securities, driving down the yields on bonds.

Rates on 15-year fixed-rate mortgages, a popular choice for refinancing, slid to 5.73 percent, from 5.83 percent last week. This week's rate hasn't been lower since the week ending Jan. 26, 2006, when 15-year rates averaged 5.70 percent.

For five-year adjustable-rate mortgages, rates edged down slightly to 5.86 percent, compared with 5.88 percent last week.

Rates on one-year adjustable-rate mortgages edged up slightly to 5.43 percent, compared with 5.42 percent last week.