DES MOINES, Iowa (AP) — The political action committee affiliated with former presidential strategist Steve Bannon acted Monday on his pledge to lead a "populist nationalist conservative revolt," endorsing state Sen. Kelli Ward over Arizona Sen. Jeff Flake — the first sitting Republican senator to be formally targeted by the pro-Donald Trump group.

"Americans are tired of the inaction from the Washington swamp and demand Senate Republicans get off their backsides and pass President Trump's America First agenda," Ed Rollins, chief strategist for Great America PAC, said in a statement.

Bannon is promoting a field of primary challengers to take on incumbent Republicans in Congress, especially the Senate. Flake has been among the Senate Republicans' most outspoken Trump critics.

The group also announced Monday it was supporting retired Marine Kevin Nicholson in Wisconsin over state Sen. Leah Vukmir in the GOP primary to challenge Sen. Tammy Baldwin, a Democrat seeking her second term.

Nicholson, a former Democrat, is among a list of outsiders Bannon is backing, including Mississippi state Sen. Chris McDaniel, who lost his challenge to Sen. Thad Cochran in 2014, and Ward, who lost to Sen. John McCain last year.

Bannon said last week he is "declaring war on the Republican establishment," and plans to recruit primary opponents for all Republican senators seeking re-election except Ted Cruz of Texas.

Bannon has also said he aims to see Senate Republican Majority Leader Mitch McConnell dumped while getting the president's agenda, including the dismantling of the 2010 Affordable Care Act and major tax cuts, enacted.

The endorsements came as Trump and McConnell worked to show public solidarity Monday during a joint press appearance. Trump said he would try to talk Bannon out of going after all GOP senators. "Some of the people that he may be looking at, I'm going to see if we talk him out of that, because frankly, they're great people," Trump said.

McConnell more directly took issue with Bannon's strategy.

"You have to nominate people who can actually win, because winners make policy and losers go home," McConnell said.