General Motors Co. has started shutting down Hummer, after a proposed deal to sell the rugged brand to a Chinese company collapsed, a senior company official said on Wednesday in Detroit.

The decision is the latest setback in GM's attempts to unload unwanted brands and alleviate slumping sales as it focuses on Chevrolet, Buick, GMC and Cadillac.

In October, Sichuan Tengzhong Heavy Industrial Machinery Co. Ltd. agreed to buy the brand, trademark, trade names and intellectual property license rights to build Hummer vehicles. The company also was going to assume existing dealer agreements.

"We are disappointed that the deal with Tengzhong could not be completed," said John Smith, GM's vice president of corporate planning and alliances. "GM will now work closely with Hummer employees, dealers and suppliers to wind down the business in an orderly and responsible manner."

In a separate statement, Tengzhong said it couldn't obtain approval from Chinese regulators within the deal's time frame

"Tengzhong is disappointed that the transaction cannot be further pursued, but the company respects the outcome," the company said.

The deal's collapse comes one day after GM finalized the sale of Saab to Dutch luxury automaker Spyker Cars NV. GM also tried to sell the Saturn brand, but that deal, too, collapsed.

GM will honor Hummer warranties and continue to provide service and parts.

Hummer sales have fallen 78.3 percent this year, the third- steepest decline behind fellow castoff brands Pontiac and Saturn. At the end of January, there were fewer than 2,500 Hummers in stock, and GM had suspended production at its Louisiana plant pending completion of the brand sale.