WASHINGTON (AP) — Average long-term U.S. mortgage rates eased slightly this week, continuing at low levels that could entice potential homebuyers.

Mortgage giant Freddie Mac said Thursday the average rate on a 30-year fixed-rate mortgage declined to 3.85 percent from 3.86 percent a week earlier. The rate on 15-year fixed-rate mortgages ticked down to 3.07 percent from 3.08 percent.

Rates have stayed below 4 percent for 10 straight weeks.

The Federal Reserve announced Sept. 17 its decision to keep interest rates at record lows for now. A rate hike by the Fed could bring higher rates for home loans. The Fed has kept the federal funds rate near zero since the financial crisis struck in 2008.

Despite the low mortgage rates, fewer Americans signed contracts to buy homes in August, as pending sales slumped amid broader concerns about the U.S. stock market and global economy.

Signed contracts to purchase homes have climbed a healthy 6.1 percent over the past 12 months, aided by steady job growth and low loan rates.

The August data issued Monday by the National Association of Realtors indicate that home sales lack the stamina to keep accelerating. Uncertainty in the financial markets and rising prices for homes are stirring doubts about affordability for many would-be buyers.

To calculate average mortgage rates, Freddie Mac surveys lenders across the country at the beginning of each week. The average doesn't include extra fees, known as points, which most borrowers must pay to get the lowest rates. One point equals 1 percent of the loan amount.

The average fee for a 30-year mortgage fell to 0.6 point from 0.7 point last week. The fee for a 15-year loan increased to 0.7 point from 0.6 point.

The average rate on five-year adjustable-rate mortgages was unchanged at 2.91 percent; the fee declined to 0.4 point from 0.5 point. The average rate on one-year ARMs was unchanged at 2.53 percent; the fee remained at 0.2 point.