The United Auto Workers union says its workers at General Motors will strike if it can't agree on a new contract with the company by 11:59 p.m. Sunday.

Both sides are still negotiating. The union made a similar threat in recent discussions with Fiat Chrysler before agreeing to a new four-year contract.

Detroit-based GM said Saturday it's working with the UAW and remains committed to reaching "an agreement that is good for employees and the business."

UAW President Dennis Williams said after the Fiat Chrysler deal that General Motors Co. and Ford Motor Co. make more money and should be able to pay more. That conflicts with company goals of cutting labor costs, bringing them closer to foreign automakers with U.S. factories.