Slideshow ( 4 images )

TORONTO (Reuters) - Workers at General Motors Co assembly plant in Oshawa, Ontario staged a sit-down protest that interrupted production for about two hours on Wednesday morning, a union spokeswoman said, following a similar protest late on Tuesday.

The action came after Unifor, the union representing the autoworkers, failed to win GM’s support for its proposals to save the plant. Unifor, which has vowed to block GM’s plan to close Oshawa by the end of 2019, met with GM officials in Detroit on Tuesday.

“Workers are now returning to the line with production expected to resume shortly,” Unifor spokeswoman Kathleen O’Keefe said. While production was affected for approximately two hours, a full shut-down was intermittent.

On Tuesday night, production stopped for nearly five hours after workers downed their tools, the union said.

It was unclear if a second shift on Wednesday would interrupt production and what impact the protests had on output.

The Oshawa plant closure, which GM has said would affect 2,973 assembly-line jobs, was announced in November as part of a broad restructuring aimed at cutting costs as investments increase in electric and autonomous vehicles.

GM has also not allocated new products for four U.S. plants, raising the possibility of their closure and the elimination of a total of about 15,000 jobs in North America.

Oshawa, which produces GM’s Chevrolet Impala, Cadillac XTS, Chevrolet Silverado and GMC Sierra, has the capacity to produce 310,000 vehicles, but its 2018 utilization was just 22 percent, according to LMC Automotive.

“We understand our union’s frustration, but need to now work together to deliver supports, transition and training for our employees,” said GM spokesman David Paterson.