FILE PHOTO: A new home is seen under construction in Los Angeles, California, U.S. July 30, 2018. REUTERS/Lucy Nicholson

WASHINGTON (Reuters) - U.S. house prices rose solidly in June, but the pace of appreciation is slowing, which together with declining mortgage rates could boost the struggling housing market.

The Federal Housing Finance Agency (FHFA) said on Tuesday its house price index increased a seasonally adjusted 4.8% in June from a year ago. That followed a 5.2% gain in May. Prices rose 0.2% on a monthly basis, matching May’s increase. They were up 1.0% in the second quarter.

The FHFA’s index is calculated by using purchase prices of houses financed with mortgages sold to or guaranteed by mortgage finance companies Fannie Mae and Freddie Mac.