Sales of previously owned homes fell unexpectedly in May as delays in processing mortgage applications hampered the closing of contracts benefiting from a popular homebuyer tax credit, an industry group said on Tuesday.

The National Association of Realtors said sales fell 2.2 percent month over month to an annual rate of 5.66 million units from an upwardly revised 5.79 million-unit pace in April.

Analysts polled by Reuters expected May sales to rise 5.5 percent to a 6.12 million-unit pace from the previously reported 5.77 million units in April.

Sales were expected to rise as transactions for existing homes are measured at contract closing. Although the tax credit for home buyers expired in April, qualified home owners have until June 30 to close contracts.

Sales were up 19.2 percent compared to May last year.

(Reporting by Lucia Mutikani; editing by Jeffrey Benkoe)