WASHINGTON — Rates on 30-year mortgages were unchanged this week, remaining at the highest level since mid-March.

Mortgage company Freddie Mac reported yesterday that 30-year fixed-rate mortgages averaged 5.88 percent again this week.

That is the highest since 30-year rates stood at 6.13 percent the week of March 16.

Since that time, rates have been below the 6 percent level for four straight weeks.

Other mortgage rates were also basically unchanged for the week.

Rates on 15-year fixed-rate mortgages, which are a popular choice for refinancing, remained at 5.42 percent, the same as last week.

Five-year adjustable-rate mortgages dipped slightly to 5.56 percent, down from 5.59 percent last week. Rates on one-year adjustable-rate mortgages slipped slightly to 5.18 percent, compared to 5.19 percent last week.