Toyota Motor, Honda, and Nissan Motor all reported strong sales for June, while sales at General Motors, DaimlerChrysler, and Ford fell.

Ford and General Motors experienced the most significant drop, as the struggling automakers scaled back on sales of fleets to buyers such as rental-car businesses, which pay discounted prices for bulk orders.

Sales at G.M. plunged 21 percent during June, a significantly greater decline than the 8 percent analysts had predicted. Car sales fell 19.3 percent, while sales of light trucks plummeted 22.8 percent.

Overall sales at Ford dropped by 8.1 percent, which marked the company's eighth consecutive monthly decline. Car sales fell 25 percent, while sales of light trucks ticked up 3 percent. Sales of crossover vehicles, including the Ford Edge and the Lincoln MKX, surged 83 percent during the month.

DaimlerChrysler, which is in the process of selling its U.S. unit to the private equity firm Cerberus Group, saw its sales decline by 1.9 percent during June. The Chrysler unit showed strength in sales of passenger cars, which were up 55 percent. But the surge wasn't enough to offset the slowdown in S.U.V.'s and trucks, which comprise nearly 70 percent of the company's total revenues.

Meanwhile, Japanese automakers all posted strong sales for June. Toyota, which for the first time sold more vehicles than General Motors during the first quarter, saw U.S. sales jump 10 percent. Its Prius hybrid car and Tundra pickup truck drove its performance during the month.

Nissan Motor reported a 23 percent increase in sales, while Honda's sales jumped 11 percent.