Sales at U.S. retailers unexpectedly fell in May for the first time since September, pulled down by a record slump in purchases of building materials, according to a government report on Friday that added to fears the economic recovery was losing some steam.

The Commerce Department said total retail sales dropped 1.2 percent, the largest decline since September, after rising by an upwardly revised 0.6 percent in April. Sales in April were previously reported to have increased 0.4 percent.

Retail sales had risen for seven straight months.

Analysts polled by Reuters had forecast retail sales rising 0.2 percent last month.

Compared to May last year, sales were 6.9 percent higher.

(Reporting by Lucia Mutikani, Editing by Chizu Nomiyama)