According to the Detroit Free Press, the UAW on Sunday morning called for a nationwide strike against General Motors, the first such strike since 2007.

The union represents about 46,000 GM autoworkers. The move follows the union saying Saturday that it would not extend its contract with GM after it expired at midnight.

The UAW said the nearly 175 union local leaders on the National Council voted unanimously to strike.

The UAW, which represents nearly 150,000 hourly workers at GM, Ford and Fiat Chrysler Automobiles, chose to negotiate a new contract first with GM. The deal will serve as a template for the UAW's later talks with the other two.

The union is bitter over GM's decision announced last fall that it would indefinitely idle four of its U.S. plants.