U.S. business inventories were unchanged in October, while total business sales fell for the second time in the past three months, the government reported Friday, raising concerns about economic growth in the fourth quarter.

The Commerce Department said October business inventories were flat following a tiny 0.1 percent rise in September. It was the weakest performance since July. Business sales fell 0.2 percent in October after being flat in September.

Overall economic activity was limited over the summer partly because businesses worked to align their inventories with weaker sales.

Economic growth slowed to a 2.1 percent annual rate in the third quarter.

Many economists believe continued weakness in inventories will dampen fourth-quarter growth as well.