By David Shepardson

(Reuters) -The United Auto Workers union said on Thursday it filed unfair labor practice charges with the National Labor Relations Board against General Motors (NYSE:) and Chrysler-parent Stellantis (NYSE:), saying they have refused to bargain in good faith.

Both GM and Stellantis denied the unfair labor charges.

Ford Motor (NYSE:) said it offered a 9% wage increase through 2027, much less than the 46% wage hike being sought by the union.

UAW President Shawn Fain said in an online remarks that the sides are far apart. “We’re going to fight like hell to get our equitable share of justice for workers,” he said.

Fain said the Detroit automakers want the ability to close U.S. auto plants and move them to low-wage countries, saying that threats by the automakers to close U.S. plants are “economic terrorism.”

Ford said its “generous offer” would provide hourly employees with 15% guaranteed combined wage increases and lump sums, and improved benefits.

“Overall, this offer is significantly better than what we estimate workers earn at Tesla (NASDAQ:) and foreign automakers operating in the U.S.” Ford said.

The union’s demands include a 20% immediate wage hike, defined-benefit pensions for all workers, shorter work weeks and additional cost of living hikes.

The current four-year labor agreements covering 146,000 workers at the Detroit Three automakers expire on Sept. 14.

Fain said neither GM nor Stellantis have made counter offers.

Stellantis said it was shocked by the UAW claims “that we have not bargained in good faith. This is a claim with no basis in fact.” Stellantis also said it was disappointed that Fain “is more focused on filing frivolous legal charges than on actual bargaining.”

GM manufacturing chief Gerald Johnson said the company strongly refuted the unfair labor charge. “We believe it has no merit and is an insult to the bargaining committees. We have been hyper-focused on negotiating directly and in good faith with the UAW and are making progress,” Johnson said.

Last week, the UAW said about 97% of voted in favor of authorizing a strike if agreement is not reached by Sept. 14.

The UAW also wants all temporary workers at U.S. automakers to be made permanent, enhanced profit sharing, substantial increase in paid time off, and the restoration of retiree health-care benefits and cost-of-living adjustments.

The UAW said Ford wants no cap on temporary workers and that those workers would not participate in profit sharing, would earn less than 60% of the top wage rate for permanent workers and receive inferior health-care benefits.

Ford said it would boost starting pay for temporary workers to $20 an hour, up 20%, and offer permanent employees $12,000 in cost-of-living adjustments over the contract.

Ford said only 2-3% of Ford’s hourly workforce are temporary employees, the lowest among the Detroit Three.

The UAW said Ford’s profit-sharing formula change would have cut payouts by 21% over the last two years, while Ford said it was offering a $5,500 signing bonus upon the contract’s ratification for permanent and temporary workers.