General Motors on Tuesday said U.S. sales fell 24 percent in June, attributing the decline to a cutback in fleet sales to daily rental companies, a "soft industry" and lower incentive spending.
The results were considerably lower than analysts' forecast of a 6 percent decline for the month, reported CNBC's Phil LeBeau.
The news came as an industry group reported that automakers across the board are deepening discounts to entice consumers to buy cars.
GM said it sold 326,300 vehicles in the U.S. last month. The results were adjusted for an extra selling day this year.
Meanwhile, Toyota Motor said its U.S. sales rose 6.1 percent on an adjusted basis in June, as incentives helped boost sales of its Tundra pickup truck.
The Japanese automaker, which has overtaken General Motors
The automaker said car sales rose 5 percent, driven by big increases in sales of its Camry sedan and the Prius hybrid vehicle. Truck sales rose 7.8 percent, boosted by a big increase in sales of the new Tundra pickup.
The results include both Toyota and Lexus brands.
Ford, the second-largest U.S. automaker, said it sold 247,599 vehicles in June, compared with 269,404 vehicles in the same month last year.
Results for Ford -- which had sought to curb its lower-margin fleet sales to car rental companies -- include its import brands and some medium- and heavy-duty trucks.
Sales at the Chrysler Group unit of DaimlerChrysler fell 5 percent on an adjusted basis to 183,347 vehicles. Chrysler Group consists of Jeep, Dodge and Chrysler brands.
The German automaker, which is in the process of selling Chrysler Group, said it sold 202,936 vehicles in June.
Automakers Deepen Discounts
Separately, industry tracking service Edmunds.com said Tuesday that automakers deepened the discounts and rebates on offer to U.S. consumers in June from a month earlier, adding incentives to slow-selling minivans and trucks.