WASHINGTON » Average long-term U.S. mortgage rates were unchanged to slightly higher this week after declining the previous week.

Mortgage buyer Freddie Mac said today the average rate on a 30-year, fixed-rate mortgage was steady at 3.71 percent. The benchmark rate also remained close to the 3.70 percent level it marked a year ago.

The average rate on 15-year fixed-rate mortgages edged up to 2.98 percent from 2.96 percent last week.

Prices of U.S. government bonds and their yields — which move in opposite directions— also showed little change over the week, in contrast to their sharp swings in recent weeks.

Mortgage rates tend to follow Treasury bond yields. The yield on the 10-year Treasury bond stood at 1.83 percent Wednesday, down from 1.87 percent a week earlier. The yield slipped to 1.82 percent this morning.

Federal Reserve Chair Janet Yellen, in a speech Tuesday, reaffirmed the Fed’s plans to move slowly in raising the interest rates it controls. That prospect could keep a lid on mortgage rates in coming weeks.

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 was unchanged from last week at 0.5 point. The fee for a 15-year loan also held steady, at 0.4 point.

Rates on adjustable five-year mortgages averaged 2.90 percent this week, up from 2.89 percent last week. The fee remained at 0.5 point.