DETROIT (AP) _ The strike in Canada is over, but thousands of General Motors workers in the United States and Mexico still can't return to their jobs and the number of those laid off keeps growing.

GM on Thursday temporarily closed its 5,000-worker Lordstown, Ohio, plant that assembles Chevrolet Cavalier and Pontiac Sunfire compacts because it's out of Canada-made parts.

And the sprawling Buick City complex in Flint, northwest of Detroit, is expected to be the next assembly operation to close _ possibly by Monday.

In Detroit, meanwhile, negotiators met again at GM headquarters as the United Auto Workers tried to bring its triennial Big Three contract negotiations to an end four months after they began.

Though there was no word on progress, negotiations were intensifying.

The Canadian Auto Workers union's strike against GM ended Wednesday when workers overwhelmingly ratified a new three-year contract.

But while most of the CAW's 26,300 members at GM were heading back to work at all but two of GM's Canadian plants, a total of 33 GM parts and assembly plants were at least partially shut south of the border.

Those plants cannot resume full production until parts from Canada are manufactured and shipped south, which in some cases could take as long as three weeks, GM says.

The Lordstown shutdown, the second and largest GM assembly plant to be closed since the Canadian strike began Oct. 2, increased the total number of GM workers on layoff in the United States and Mexico to 23,801.

GM spokesman Tom Klipstine said the Lordstown plant is expected to be idle for a couple of weeks. It was closed after the first shift ended Thursday.

The Buick City complex in Flint is the only other GM assembly plant that could face a shutdown.

``We're keeping a close eye on the situation and it will be re-evaluated tomorrow,'' Klipstine said.

The GM-UAW talks were believed to be focused on the same major issue that led to the strike in Canada: outsourcing, the practice of contracting out parts work to outside, lower-cost suppliers.

But the UAW has made no strike threats against any of the Big Three in this round of talks.

The union settled earlier with Ford Motor Co. and Chrysler Corp. The CAW plans to begin talks with Ford on Monday, with a contract deadline of Nov. 6. It settled earlier with Chrysler.