Thousands more employees at Detroit’s Big Three will walk off the job Friday afternoon, the first escalation in the United Auto Workers’ week-old strike and a setback for President Joe Biden’s hopes of an early end to the dispute.

UAW President Shawn Fain announced that parts distribution workers at 38 locations across 20 states will join the roughly 12,700 union members taking part in the initial three-plant strike that began Sept. 15 against Ford, General Motors and Stellantis.