Average fixed mortgage rates in the U.S. fell to the lowest levels since May 2013 in the latest week, according to mortgage-finance company Freddie Mac (FMCC).

The decline came in a week when the yield on the benchmark 10-year note fell below 2% for the first time in three months.

Freddie Mac Chief Economist Frank Nothaft stated Thursday that minutes from the Federal Reserve's most recent meeting "indicated ongoing discussion regarding the timing of the first rate hike." Meanwhile, a private national employment report compiled by payroll processor Automatic Data Processing Inc. (ADP) and forecasting firm Moody's Analytics also indicated that businesses hired more workers that expected during December, Mr. Nothaft also noted.

For the week ended Thursday, the 30-year fixed-rate mortgage averaged 3.73%, the lowest level since May 2013, when the rate averaged 3.59%. The 30-year fixed rate was 3.87% a week earlier and 4.51% a year earlier.

Rates on 15-year fixed-rate mortgages averaged 3.05%, compared with 3.15% the previous week and 3.56% a year earlier.

Five-year Treasury-indexed hybrid adjustable-rate mortgages, or ARMs, on average, was at 2.98%, compared with 3.01% the previous week and 3.15% a year earlier. One-year Treasury-indexed ARM rates on average were 2.39%, compared with 2.4% the previous week and 2.56% a year earlier.

Write to Tess Stynes at tess.stynes@wsj.com

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