WASHINGTON — Rates on 30-year mortgages jumped to the highest level in five weeks as investors expressed disappointment that the Federal Reserve remains worried about inflation.

Mortgage giant Freddie Mac reported yesterday that 30-year fixed-rate mortgages averaged 6.21 percent nationwide this week, up from 6.15 percent last week. It was the highest level for 30-year mortgages since they averaged 6.22 percent the week of April 12.

Mortgage rates have been relatively stable since the beginning of the year, with the 30-year fluctuating in a narrow range that saw it go as high as 6.34 percent in early February and as low as 6.14 percent for the first two weeks in March.

Freddie Mac said its survey found that other types of mortgages increased this week.

Rates on 15-year fixed-rate mortgages, a popular choice for refinancing, rose to 5.92 percent this week, up from 5.87 percent last week.

Five-year adjustable-rate mortgages averaged 5.92 percent this week, up from 5.89 percent last week.

One-year adjustable-rate mortgages, which had shown the biggest upward movement last week, were unchanged this week at 5.48 percent.