The United Auto Workers filed a complaint today to the National Relations Board on behalf of hundreds of Tesla factory workers who were fired from the assembly plant last week. The UAW posted a copy of the complaint made against Tesla on its website, which alleges that pro-union workers were unfairly targeted.

The UAW says the complaint was made on Wednesday to the Oakland offices of the National Relations Board. The union claims the recent culling of several hundred Tesla employees included many who were involved in a pro-union movement at the Fremont assembly plant, and included those who wore pro-union shirts and stickers.

The Fremont factory site has roots in the UAW. It was once a former joint manufacturing facility owned by GM and Toyota, until it closed in 2010. Despite ongoing efforts, under Tesla’s ownership, the factory is not unionized. A pro-union rally was held Tuesday in front of the plant, which was documented in a Facebook post by the pro-union group A Fair Future at Tesla.

The UAW’s action follows a lawsuit filed on Tuesday by a former employee. Abraham Duarte’s complaint filed in Alameda County Superior Court alleges Tesla failed to provide adequate notice for layoffs under the California WARN Act, Jalopnik reported. Duarte’s attorney claims Tesla used performance reviews as a cover for company-instituted layoffs so it would not have to provide 60 days of notice to terminate 50 or more employees. In a statement to Jalopnik, Tesla said the terminations were due to performance reviews, and that it is hiring and creating new positions at all of its facilities.

Since the first terminations at the Fremont factory on October 13th, two lawsuits have been filed against Tesla. The allegations include racial harassment and anti-LGBT harassment at the Fremont facility.

In addition to the recent firings, Tesla-owned SolarCity reported Tuesday that it made layoffs. The companies have terminated an estimated 1,200 employees in the last month, according to CNBC. The first cuts were reported by The Mercury News one week after CEO Elon Musk announced the Tesla Semi truck unveiling would be delayed nearly a month, in part to focus on the Model 3 “production hell” that has stifled production of its mainstream car.

We’ve reached out to Tesla for comment. The company is scheduled to announce its third-quarter earnings on Wednesday.