Updated from 12:37 p.m. EDT

Higher gas prices continued to weigh on Detroit in June, with all three major U.S. manufacturers posting big drops in U.S. sales as demand for trucks declined.

The world's largest automaker, General Motors ( GM), suffered a 26% drop in U.S. sales for the month. The company faced difficult comparisons to last year, when it posted a 41% jump in June sales after it began offering all U.S. customers its "employee discount." This year, it's offering more limited discounts.

GM sold 413,473 vehicles in June, compared with 558,092 last year. Car sales declined 2.3%, while truck sales dropped 37%.

Last week, the company warned that it had a "brutal" June compared with last year. On a conference call with Wall Street after the release on Monday, the company's executive director, Paul Ballew, said the final results for the month were "better than expected."

GM made no changes to its production plans.

Ford's total sales fell 6.9% to 269,404 vehicles from 289,449 a year earlier. Truck sales sank 14% to 161,796 trucks from 189,011 last year. The drop offset a 7.1% rise in car sales, which increased to 107,608 cars from 100,438 last year.

"After the sharp run-up in gasoline prices in April, some truck buyers delayed purchases," said Al Giombetti, president of Ford and Lincoln Mercury marketing and sales, in a statement. "Truck buyers are not as likely as SUV buyers to leave the segment, but some buyers are deferring purchases to balance higher monthly payments and higher fuel costs."

Ford's SUVs were among its worst-selling brands. The Ford Expedition had a 46% sales decline in June, and sales of Ford Explorers dropped 36%.

Ford shares recently were down 22 cents, or 3.2%, to $6.71.

DaimlerChrysler, meanwhile, said sales in the U.S. fell 13% to 206,748 vehicles from 238,724 last June. Sales at Chrysler Group -- consisting of the Jeep, Chrysler and Dodge brands -- tumbled 15% to 185,946 units from 220,032 last year. The Mercedes-Benz USA division saw a 14% rise in sales to 20,802 vehicles.

Declines from Detroit's so-called Big Three drew a sharp contrast from the 14.4% jump in sales for the month posted by Toyota ( TM. ). Its U.S. arm sold 223,018 vehicles in June, led by a 22% jump in passenger-car sales.

"Fuel-efficient products continue to drive the market, even as consumers are likely becoming acclimated to today's fuel prices," Toyota said in a statement.