DETROIT — General Motors and the Canadian auto workers union Unifor have reached a tentative contract agreement, averting a strike that was threatened for midnight Monday.

Union President Jerry Dias said the deal will bring new products to the Oshawa assembly plant near Toronto and an engine plant in St. Catherines, Ontario. Details were few at an early morning press conference in Toronto, but Dias said workers will get pay raises and lump-sum payments, and about 700 temporary employees at the plants will go full-time if the deal is ratified by members.

With the agreement, Unifor won on its most important issue, securing a future for the two Ontario factories. The deal brings an end to fears that GM would close the Oshawa plant. The three cars it makes, the Cadillac XTS, Chevrolet Impala and Buick Regal, are scheduled to go out of production in 2019. The factory also makes the Chevrolet Equinox crossover SUV, but its production there is scheduled to end in July of next year.