WASHINGTON (AP) — The average U.S. rate on the 30-year fixed mortgage rose this week after falling to new record lows in each of the past 13 weeks.

Mortgage buyer Freddie Mac said Thursday that the rate on the 30-year loan jumped to 3.55 percent. That's up from 3.49 percent last week, which was the lowest since long-term mortgages began in the 1950s.

The average rate on the 15-year fixed mortgage, a popular refinancing option, increased to 2.83 percent. That's above last week's record low of 2.80 percent.

Cheaper mortgage rates have helped drive a modest but uneven housing recovery this year. Sales of new and previously occupied homes fell in June from May but were higher than the same month last year. Home prices have started to rise in a majority of cities.

Builders are also more confident after seeing more demand for homes. In June, they increased their spending for a third straight month.

Low mortgage rates could also provide some help to the economy if more people refinance. When people refinance at lower rates, they pay less interest on their loans and have more money to spend. Many homeowners use the savings on renovations, furniture, appliances and other improvements, which help drive growth.

Still, the pace of home sales remains well below healthy levels. Many people are still having difficulty qualifying for home loans or can't afford larger down payments required by banks.

The sluggish job market could deter some from making a purchase this year. The Labor Department reports Friday on July unemployment and job growth.

The Federal Reserve said Wednesday that the economy is losing strength and repeated a pledge to take further steps if the job market doesn't show sustained improvement.

The Fed took no new action after its two-day meeting. But it acknowledged that economic activity had slowed over the first half of the year, unemployment remains elevated and consumer spending has weakened.

Mortgage rates have been dropping because they tend to track the yield on the 10-year Treasury note. A weaker U.S. economy and uncertainty about how Europe will resolve its debt crisis have led investors to buy more Treasury securities, which are considered safe investments. As demand for Treasurys increase, the yield falls.

To calculate average rates, Freddie Mac surveys lenders across the country on Monday through Wednesday of each week.

The average does not 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 30-year loans was 0.7 point, unchanged from last week. The fee for 15-year loans slipped to 0.6 point from 0.7 the previous week.

The average rate on one-year adjustable rate mortgages fell to 2.70 percent from 2.71 percent. The fee for one-year adjustable rate loans declined to 0.4 point from 0.5 point.

The average rate on five-year adjustable rate mortgages rose to 2.75 percent from 2.74 percent last week. The fee was unchanged at 0.6.