WASHINGTON, Sept 24 (Reuters) - Sales of new U.S. single-family homes rose more than expected in August, but there are signs that housing market momentum is slowing as the tailwind from the COVID-19 pandemic fades. New home sales increased 1.5% to a seasonally adjusted annual rate of 740,000 units last month, the Commerce Department said on Friday. July’s sales pace was revised up to 729,000 units from the previously reported 708,000 units. Economists polled by Reuters had forecast new home sales, which account for a fraction of U.S. home sales, increasing to a rate of 714,000 units. (Reporting by Lucia Mutikani; Editing by Andrea Ricci)