Mortgage rates held the line this week, remaining at three-month lows, with the average rate on 30-year, fixed-rate mortgages remaining just above 5%, according to Freddie Mac's (FRE) weekly survey of mortgage rates.

After yields on Treasurys rebounded from the multi-decade lows they hit earlier this year, they have since retraced a bit - taking mortgage rates along with them.

Freddie chief economist Frank Nothaft noted Thursday that the results, which ended three straight weeks of declines in fixed mortgage rates, come on the heels of the Mortgage Bankers' Association reporting a 13% jump in mortgage applications last week. The results, boosted by refinancings, were the strongest since May.

Earlier Thursday, however, National Association of Realtors data showed that existing-home sales in the U.S. unexpectedly fell in August after a string of increases that took them to a two-year high. The Federal Reserve, in a move aimed at keeping interest rates low for home buyers through early next year, decided to extend and gradually phase out its purchase of mortgage-backed securities.

Freddie said the 30-year fixed-rate mortgage averaged 5.04% for the week ended Thursday, unchanged from last week's average and down from the year earlier's 6.09%. Rates on 15-year fixed-rate mortgages were 4.46%, compared with 4.47% and 5.77%, respectively.

Five-year Treasury-indexed hybrid adjustable-rate mortgages averaged 4.51%, flat with last week but down from 6.02% a year earlier. One-year Treasury-indexed ARMs were 4.52%, dropping from 4.58% and 5.03%, respectively.

To obtain the rates, all but the 5-year adjustable required payment of an average 0.6 point. A point is 1% of the mortgage amount, charged as prepaid interest. The 5-year adjustable needed 0.5 point.

-By Mike Barris, Dow Jones Newswires; 212-416-2330; mike.barris@dowjones.com;