The United Auto Workers union is expanding its strike against GM and Stellantis but said progress in negotiations with Ford meant it will not add to workers already picketing that company.

UAW President Shawn Fain made the announcement on Friday morning. "At noon Eastern today, all parts distributions centers at General Motors and Stellantis will be on strike," he said. "We will shut down parts distribution until those two companies come to their senses and come to the table with a serious offer."

But Fain said that there has been significant improvement in offers from Ford and that is the reason the strike will not be expanded there.

"We do want to recognize that Ford is serious about reaching a deal," he said.

The strike will now expand to GM's and Stellantis's 38 parts and distribution centers. The distribution centers generally send parts to dealerships to be used for repairs, so the move could quickly cripple dealerships ability to do repairs, which is the most profitable part of their business.

Still the announcement of progress at Ford raised hopes that the strike, at least at there, could be brought to a relatively quick end. Before Friday, there had been few public signs that the union and management of the three companies were anywhere close to an agreement.

The announcement comes just days after Ford reached a tentative deal with the Canadian union Unifor, which averted a strike by more than 5,000 autoworkers in that country that would have should down its three factories there.

As of 10:30 am ET, Stellantis (STLA) is up 0.98%; Ford (F) is up 3.57%; and GM (GM) is up 0.7%.

This is a developing story. It will be updated.