WASHINGTON (AP) — Average long-term U.S. mortgage rates eased this week after hitting their highest levels this year in the previous week.

Mortgage giant Freddie Mac said Thursday the average rate on a 30-year fixed-rate mortgage declined to 4 percent this week from 4.04 percent a week earlier. The rate on 15-year fixed-rate mortgages slipped to 3.23 percent from 3.25 percent.

Mortgage rates have been surging in recent weeks amid signs of improvement in the economy.

On Wednesday, the Federal Reserve took note of the economic strength and appeared ready to raise interest rates this year for the first time in nearly a decade, in the belief that the economy no longer needs the stimulus of near-zero rates.

The economic improvement and stronger employment picture has bolstered the housing market. In a recent indication, the government reported Tuesday that although U.S. builders broke ground on fewer homes in May, the pace of construction remains significantly higher than a year ago.

The recent increase in mortgage rates has come during the height of the spring home buying season. Still, mortgage rates remain low by historic standards. A year ago, the average 30-year rate was 4.17 percent and the 15-year was 3.30 percent.

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 rose to 0.7 point from 0.6 point last week. The fee for a 15-year loan fell to 0.5 point from 0.6 point.

The average rate on five-year adjustable-rate mortgages slipped to 3 percent from 3.01 percent; the fee was unchanged at 0.4 point. The average rate on one-year ARMs was steady at 2.53 percent; the fee remained at 0.2 point.