In total, the strike now includes approximately 25,000 people in 21 states.
According to union president Shawn Fain, the latest strike concerns two factories in Chicago and Michigan, respectively, where work was stopped starting Friday afternoon.
“Our brave members at these two plants are our next wave of reinforcements in the fight for record deals,” Fain said.
The union began the strike on September 14 and now includes a total of around 17 percent of the 146,000 members.
The UAW initially demanded wage increases of 40 percent over four years, a figure that has since been slightly adjusted down.
The employers are said to have offered 20 percent wage increases in four years and other improvements in terms and conditions. It is described as the most generous offer put forward in decades.