The union also informed its workers that an agreement had been reached, but advised workers, on strike since April 17, to remain on the picket line until the agreement had been ratified by a union vote, the Detroit Free Press reported.

GM has been hit by a series of strikes this year. Workers remain on picket lines at GM plants in Kansas City, Kan., while work shortages continue at more than 30 other plants affected by a strike at parts supplier American Axle and Manufacturing Inc.