The United Auto Workers union has decided not to expand its strikes against Detroit's three automakers after General Motors made a breakthrough concession on unionizing electric vehicle battery plants.

Union President Shawn Fain told workers in a video appearance Friday that additional plants could be added later. The delay came shortly after GM agreed to bring electric vehicle battery plants into the UAW's national contract, essentially assuring that they will be unionized.

Fain said GM's move will change the future of the union and the auto industry.

He said GM made the change after the union threatened to strike at a GM plant in Arlington, Texas, which makes highly profitable large SUVs.

“Today, under the threat of a major financial hit, they leapfrogged the pack in terms of a just transition” from combustion engines to electric vehicles, he said. “Our strike is working, but we’re not there yet.”