U.S. wholesalers increased their stockpiles in July from June, but sales fell for a third straight month. Declining sales could force companies to cut inventories in coming months, a troubling sign that growth could weaken.

The Commerce Department says wholesale stockpiles grew 0.7 percent in July, the biggest increase in five months.

Sales fell 0.1 percent following declines of 1.4 percent in June and 1.1 percent in May. That marked the longest stretch of weakness since seven straight monthly declines ending in January 2009, a period when the country was in recession.

The slump in sales means it will take wholesalers longer to clear out their stockpiles and could result in cutbacks in orders to factories. That would mean less production and weaker economic growth.