TORONTO — General Motors and the union representing Canadian auto workers have reached a tentative contract agreement, ending a strike that began just after midnight Tuesday. About 4,300 striking workers at two GM factories and a parts warehouse returned to work Tuesday afternoon and will vote on the three-year deal later.

Unifor union president Lana Payne said, when faced with the strike, GM had no choice but to follow a pattern agreement reached earlier with Ford. GM said it reached the three-year agreement around 1 p.m. Tuesday after workers went on strike at the Ontario facilities. GM said the deal recognizes employee contributions with significant pay and benefit increases and additional job security.