DETROIT - General Motors Co  will wind down its Hummer SUV line after failing to complete a deal to sell the brand to China's Sichuan Tengzhong Heavy Industrial Machinery, the automaker said on Wednesday.

GM had been trying to complete the deal by the end of February after reaching a definitive agreement last year to sell Hummer to Tengzhong, a little-known heavy machinery company based in Sichuan province.

But the two companies failed to win approval for the deal from Chinese regulators within the proposed time frame, Tengzhong said in an emailed statement to Reuters.

The collapse of the deal represents another setback for GM, which had been working to shed unprofitable brands and focus on its four core brands -- Chevrolet, Cadillac, Buick and GMC -- after emerging from bankruptcy in July.

We are disappointed that the deal with Tengzhong could not be completed, John Smith, GM vice president of corporate planning and alliances, said in a statement.

GM will now work closely with Hummer employees, dealers and suppliers to wind down the business in an orderly and responsible manner, Smith said.

GM said it will continue to honor warranties and provide service support and spare parts to current Hummer owners.

This marks the third sale of a GM brand that has fallen through or been abandoned by the automaker, which was restructured in bankruptcy last year, backed by some $50 billion in U.S. taxpayer funding.

A tentative deal reached by GM to sell its Saturn brand to Penske Automotive Group Inc also collapsed at the end of September, just before it was expected to close.

GM also scrapped a plan to sell its Germany-based Opel unit to a group led by Magna International last year.

First seen as multipurpose, off-road military vehicles, Hummers were originally built by AM General. Its first model was the Humvee, built for the military. GM bought the Hummer brand from AM General in 1999. AM General still makes the Humvee for the U.S. military.

The privately owned Tengzhong was formed in 2005 through several mergers and has fewer than 5,000 employees.

(Reporting by Soyoung Kim, editing by Matthew Lewis)