Nov 8 (Reuters) - United Auto Workers President Shawn Fain said on Wednesday the union will "pull out all stops" in working to organize non-union U.S. auto plants after winning new contracts with the Detroit Three automakers.

Fain will join President Joe Biden on Thursday in Belvedere, Illinois to tout Chrysler-parent Stellantis decision to reopen a shuttered assembly plant there. In an video interview at the Reuters Events auto conference in Detroit, Fain said the UAW is aggressively working on its organizing plans.

"We're going to pull out all stops. We're going to leverage every avenue we can and we're going to find creative ways to get to workers," Fain said. "We're going to employ everything we can to support workers and give them what they need."

He said hundreds of autoworkers at nonunion plants have reached out to the UAW seeking to join.

Fain said the UAW deserved credit for Toyota Motor decision's last week to raise the wages of nonunion U.S. factory workers. He said previously Toyota hiked wages "because the company knows we're coming for 'em."

Days after the UAW won major pay and benefit hikes from the Detroit Three automakers, Toyota announced that hourly manufacturing workers at top pay will receive a wage hike of about 9% effective on Jan. 1 and cut the time needed to get top pay from eight to four years.

The UAW has tried and failed for years to organize nonunion U.S. auto factories, most of them built by Asian and European legacy automakers in southern U.S. states where so-called "right to work" labor laws make it optional for workers to pay union dues.

"When we return to the bargaining table in 2028, it won’t just be with the Big Three, but with the Big Five or Big Six," Fain said.

Fain praised Biden administration officials for helping the union win agreements with the Detroit Three automakers to ensure battery plant workers get higher wages and benefits.

Fain and Biden on Thursday will tout Stellantis decision to build a new $3.2 billion battery plant and invest $1.5 billion in a new mid-size truck factory in Illinois under its tentative labor agreement. The UAW has not yet endorsed Biden for re-election saying it is focused on winning ratification of the labor deals.

"We're going to make endorsements at the proper time," Fain said. (Reporting by David Shepardson and Joseph White; Editing by David Gregorio)