Tesla is not producing enough Model 3s per shift to reach the 5,000 per week target that CEO Elon Musk said it would reach by Saturday, three line workers at the company’s Fremont, California, assembly plant told Reuters this week.

The company was able to assemble and paint 210 Model 3s during the first of two 12-hour shifts on Wednesday, one worker told Reuters. On one of two Monday shifts, the company produced 305 of the vehicles, another worker told Reuters. The number of vehicles assembled per shift is displayed for line workers in the plant.

The company is running two 12-hour shifts per day every day this week on the Model 3, the two workers who provided the production figures said. If the company produces 300 Model 3 vehicles during all 14 shifts, it would produce 4,200 cars for the week.

Tesla declined to comment on its production numbers or on employee reports of problems.

The Model 3, initially promised at a base price of $35,000, is meant to be the mass market vehicle that can propel electric-powered vehicles into the mainstream and Tesla into profitability. But Tesla has struggled to produce the volume of cars it needs because of problems with the assembly line and other snafus.

The company’s Fremont, California, factory has also been plagued by a series of fires, including at least two in June.