Tesla Motors has fired hundreds of employees following an annual review despite plans to ramp up production of their Model 3 sedan, reports CBS News.

Tesla did not reveal how many of its 33,000 workers were let go from the company, but the San Jose Mercury News interviewed multiple former and current employees who estimate that the number is somewhere between 400 and 700.

Employees were fired across many of the company’s departments, from administration to sales to manufacturing. A number of other employees, however, received bonuses and promotions based on their previous work, according to the company.

“As with any company, especially one of over 33,000 employees, performance reviews also occasionally result in employee departures,” a spokesman told the Mercury News. “Tesla is continuing to grow and hire new employees around the world.”

Of those fired, many were pro-union, leading some to believe they were let go for their union activities. Tesla has denied this, stating that union memberships played no role in its decision. The company, however, faces a hearing before the National Labor Relations Board in November over claims that supervisors and security guards allegedly harassed workers distributing union information, something Tesla denies.

Production worker Juan Maldonado was among the many fired after working at Tesla for nearly four years. In an interview with Mercury News, Maldonado said approximately 60 other employees were let go from his department for various reasons. While he recalled being late for work twice in recent months, Maldonado believes these issues were resolved with his supervisor.

Approximately 450,000 customers have paid $1,500 to add their names to a waiting list for Tesla’s new Model 3 sedan as pressure to deliver the cars mounts. The car manufacturer has lagged behind on its production schedule for some time, only producing 260 of the popular model last quarter. Tesla CEO Elon Musk joked to staff that they would be in “production hell” to meet demand.

Michael Harley, a managing editor at Kelley Blue Book and Autotrader, told Mercury News, he believes that the mass layoffs could be an attempt to improve vehicle production. “It’s no secret that Tesla’s Model 3 development and ramp-up for production has been derailed,” said Harley. “A major change in staff, whether dismissal or layoff, is an indication that there is an upper-level movement to put the train back on the tracks.”

Lucas Nolan is a reporter for Breitbart News covering issues of free speech and online censorship. Follow him on Twitter @LucasNolan or email him at lnolan@breitbart.com