SHREVEPORT, La. (AP) -- General Motors Corp. will close its assembly and stamping plants in Shreveport, La., no later than June 2012, the company said Wednesday.

GM spokesman Chris Lee said the Shreveport operation, which employs 950 people, was added to the nine permanent plant closings, along with the idling of three others, announced when the company filed for bankruptcy protection on June 1.

Shreveport will continue to assemble Chevrolet Colorado and GMC Canyon pickup trucks based upon market demand, but with production ending no later than June 2012. The plants "will not be allocated any new products," Lee said.

The plants also assemble the commercial Hummer H3 and H3T pickup truck. GM has tentatively agreed to sell the commercial Hummer brand to Sichuan Tengzhong Heavy Industrial Machinery Co. during the third quarter. A Hummer spokesman earlier said that the buyer had planned to move the annual production of about 10,000 Hummers from South Africa to Shreveport.

Lee said that if the deal goes through, Hummer production in Shreveport would continue for a yet-to-be determined period of time that will be decided by the new owner.

It had been widely hoped that the operation would continue after it escaped the initial plant closure list released in June.

But Doug Ebey, president of the United Auto Workers Local 2166, said GM's decision "was a big shock to us" even though the union had been "hearing rumblings for some time."

On June 1, GM said it would shutter another plant by the end of 2012, though it did not identify it. Lee said the company felt it would be inappropriate to discuss the Shreveport operation at that time because negotiations with Sichuan Tengzhong had not been completed.

The Shreveport plants are currently idle as part of a systemwide GM production cutback.

Following $1.5 billion in investments in recent years, the Shreveport assembly plant was considered one of the company's most modern -- but its products wound up on the short end of skyrocketing gasoline prices last year, followed by the economic meltdown in October and the company's free-fall.

The pickups and the Hummers fell out of favor with consumers as fuel prices rose.

The plants once employed about 3,000 people but were down to one shift -- with frequent production shutdowns as inventory piled up on dealers' lots.

For Carey Mincey, a 23-year GM worker, it would be his third plant closure. Mincey, an electrician at the assembly plant, said he previously was displaced by GM closures in Tarrytown, N.Y., in 1996 and Tuscaloosa, Ala., in 2002. He said he needed seven more years for full retirement.

"I was really hoping we'd make it," Mincey said. "I've been a GM gypsy. Hopefully, there will be another place for them to send me."

State Rep. Wayne Waddell, R-Shreveport, said the announcement wasn't a surprise to him.

"I was very concerned about that plant, had been for quite a while. And 2012, that'll get here quick," Waddell said.

Waddell said there is some chance that trained former GM workers in Shreveport might commute or move to Monroe, if and when a new auto plant being planned by a startup company opens there.

San Diego-based V-Vehicle Co. has won state financial incentives and is seeking further funding to use the now-vacant Guide Corp. plant in Monroe -- which once made vehicle headlights -- into an assembly plant for a next-generation, fuel-efficient car. The plant would have a payroll of 1,400 at an average salary of $40,000, officials said.

AP writer Doug Simpson in Baton Rouge, La., contributed to this report.