EXCLUSIVE: Republican Sen. Mike Lee is taking sides in Missouri's crowded Republican Senate primary for the race to succeed retiring GOP Sen. Roy Blunt.

Lee, the two-term conservative senator from Utah, endorsed Missouri attorney General Eric Schmitt Tuesday in an announcement shared first with Fox News.

CRUZ BACKS SCHMITT IN MISSOURI'S COMPETITIVE GOP SENATE PRIMARY

"As Attorney General, Eric Schmitt has been a relentless fighter who has taken action at every turn to stop the Biden administration's radical agenda," Lee said in a statement. "Eric Schmitt is the only candidate in Missouri’s U.S. Senate primary that has the Conservative credentials needed to deliver Republican victories for our nation. He has my strongest endorsement."

Sen. Mike Lee speaks at Capitol news conference

Sen. Mike Lee, R-Utah.,  speaks during a news conference in the Capitol on Tuesday, July 20, 2021. (Bill Clark/CQ-Roll Call, Inc via Getty Images)

In thanking Lee for his endorsement, Schmitt said "look forward to standing alongside him to fight back against illegal immigration, take on government overreach, and stand for the rule of law."

Lee is the second high-profile Senate Republican to back Schmitt, following conservative firebrand Sen. Ted Cruz, R-Texas, who endorsed Schmitt in February.

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Schmitt, who’s won two statewide elections in Missouri — for treasurer and then attorney general — has made headlines over the past year and a half filing lawsuits against President Biden’s administration. He is one of over 20  Republicans vying for their party’s nomination in the state’s Aug. 2 primary.

Missouri Attorney General Eric Schmitt campaigns for the GOP Senate nomination

Republican Attorney General Eric Schmitt of Missouri, a leading contender for the state's GOP Senate nomination, greets voters at the Texas County and Shannon County Lincoln Days gathering, on June 11, 2022  (Eric Schmitt Senate campaign )

Schmitt is considered a major GOP contender in the race, along with former Gov. Eric Greitens, who left office in 2018 amid multiple controversies, as well as Rep. Vicky Hartzler in Missouri’s 4th Congressional District, in the predominantly rural west-central part of the state, Rep. Billy Long in the state’s 7th Congressional District in southwest Missouri, and Mark McCloskey, the St. Louis attorney who along with his wife grabbed national headlines during the summer of 2020 for holding guns outside their home to warn off Black Lives Matter protesters.

And Schmitt, along with Greitens and Hartzler, are considered the polling front-runners in the Republican contest. To date, former President Donald Trump remains neutral in the primary battle. The GOP primary winner will be considered the front-runner in Missouri, which was once a competitive state but has trended Republican for well over a decade.

GREITENS HEAVILY CRITICIZED BY BOTH DEMOCRATS AND REPUBLICANS FOR ‘RINO HUNTING’ VIDEO

Greitens on Monday was heavily criticized by both Democrats and Republicans for a campaign video released by his team. In the ad, Greitens touts his Navy SEAL service in the video, as he’s seen breaking into a house — while holding a shotgun and flanked by a tactical team — and going on what he called "RINO hunting," encouraging the "bagging and tagging" of moderate Republicans with a "RINO hunting permit."

The videos’ release comes amid a heightened national focus on political violence, following recent fatal mass shootings and threats to government officials.

And the controversy is the latest to surround Greitens, who been trying to move past graphic allegations of domestic abuse and violence made by his ex-wife in a sworn affidavit filed in March in their child custody case.

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The Schmitt campaign originally reacted to the Greitens video with an eye roll emoji. 

Asked by Fox News on Tuesday for a statement, Schmitt campaign spokesman Rich Chrismer said "like so many things involving Eric Greitens, this is clearly a cry for attention to satisfy his own ego. We trust Missouri primary voters will send a real fighter in Eric Schmitt to the Senate not a quitter like Eric Greitens."

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Evan McMullin, a former CIA officer and Republican turned independent who's launched a third party challenge against Lee in Utah's Senate race, condemned the Greitens video and urged Lee to do likewise.