DETROIT - General Motors Corp. plans to cut 15 percent of its U.S. and Canadian salaried work force — or around 5,100 jobs — by Nov. 1 as part of a plan to slash billions of dollars and help the automaker ride out a slump in U.S. sales.

A GM official declined to confirm the specific numbers but indicated they were generally accurate. The official asked not to be named because the company had not planned to release the numbers until later.

Word of the cuts came two days before GM plans to release its second-quarter earnings. Analysts surveyed by Thomson Financial are predicting a loss of $2.63 per share amid plummeting truck and sport utility vehicle sales.

GM said in mid-July that it would cut white-collar costs in the U.S. and Canada by more than 20 percent as part of a larger cost-cutting plan, but it wouldn't say how many workers would leave.

GM President and Chief Operating Officer Fritz Henderson said at the time the company hoped most of the cuts would be made through attrition, retirements and buyout offers, but that the company would consider involuntary layoffs.

GM, Ford Motor Co. and Chrysler LLC have announced salaried layoffs in recent weeks as the U.S. market stumbles through its slowest year in more than a decade. Ford plans to cut 15 percent of its salaried costs by Friday, while Chrysler plans to cut 1,000 salaried jobs worldwide by Sept. 30.

Nissan North America Inc. also offered buyouts to around 6,000 salaried and hourly employees at its two Tennessee plants Wednesday.

GM announced the cost-cutting plan July 15 after its shares hit a 54-year low. The automaker said it planned to save $15 billion by cutting salaried and hourly jobs, selling assets, suspending its dividend and eliminating health care for salaried retirees over age 65.

GM shares fell 55 cents, or 4.6 percent, to $11.55 in afternoon trading.