FREMONT — Several dozen Tesla workers, family members and union supporters protested Tuesday at the automaker’s factory, seeking the reinstatement of some of the hundreds of recently fired employees.

A coalition of labor groups also blasted the electric vehicle maker in a letter to Tesla executives, questioning whether union-supporters were dismissed because they publicly raised issues about wages and safety at the plant.

“Among the fired workers are people who have raised their voices with concerns about health and safety risks, fair pay and the right to organize free from intimidation, and we are concerned that these workers may have been unjustly fired for doing so,” union representatives wrote to Gaby Toledano, chief people officer at Tesla. “We are calling for reinstatement of these workers and fair treatment for all employees.”

Tesla fired several hundred employees this month after annual reviews. The company insisted the workers were let go because of poor performance, while others were rewarded with promotions and raises.

A Tesla spokesman said the company strives to be fair with its workers.

“No one at Tesla has ever or will ever have any action taken against them based on their feelings on unionization,” the spokesman said.

About 17 percent of the company’s employees were promoted, he said, and almost half of those promotions were at the factory.

Workers have told this news organization that between 400 and 700 employees were fired. Union organizers believe the count may be as high as 1,000 workers. The company employs about 33,000 workers, including about 10,000 at its Fremont factory.

Several former workers said in interviews they believed pro-union workers were targeted during the deep cuts.

Mike Williams, a former production associate and union supporter, said in a statement Tuesday that he was fired without explanation after five years.

“I have my most recent performance review, and it says that I was ‘consistently strong,'” Williams said. “I have had no write-ups, no complaints against me. I do not believe I was fired for performance.”

The widespread firings — ranging from factory workers in Fremont to engineers at the Palo Alto headquarters — come at a crucial production time for Tesla. The company is ramping up to mass produce its lower-cost Model 3 sedans. Tesla has about 450,000 reservations for the all-electric car, but produced just 260 last quarter.

The company also continues to struggle financially, losing $336 million in the second quarter. Tesla stock dipped in the last week, but is still near record highs.

The National Labor Relations Board is also investigating whether Tesla harassed workers distributing union materials.

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The letter was sent by the labor councils of Alameda, San Francisco, San Mateo and South Bay, and the California Labor Federation, East Bay Alliance for a Stronger Economy, Silicon Valley Rising and Working Partnerships USA.

The protesters were joined by local elected officials and clergy members, and carried pro-union signs through the factory parking lot.