WASHINGTON, July 26 (Reuters) - Sales of new U.S. single-family homes tumbled in June and sales in the prior month were weaker than initially estimated, suggesting the housing market was losing momentum amid soaring prices that are being driven by an acute shortage of properties. New home sales dropped 6.6% to a seasonally adjusted annual rate of 676,000 units last month, the Commerce Department said on Monday. May’s sales pace was revised down to 724,000 units from the previously reported 769,000 units. Economists polled by Reuters had forecast new home sales, which account for a small share of U.S. home sales, increasing 3% to rate of 800,000 units in June. (Reporting by Lucia Mutikani; Editing by Andrea Ricci) Our Standards: The Thomson Reuters Trust Principles.