The Club for Growth fired its first salvo at Rep. Markwayne Mullin on Monday as it moves to oust the Oklahoma Republican in the midterm primary.

The conservative advocacy group is releasing a short ad, running digitally and on local television, criticizing Mullin on fiscal issues and on abandoning a self-imposed term limits pledge. Sources say the club is simultaneously recruiting a challenger to take the incumbent in the 2nd District GOP primary.

“Is Markwayne Mullin losing his memory? First Mullin forgot about his term limits promise. Then he complained about spending,” the ad’s voice-over says. "But now [he] wants to bring back earmarks — special interest spending scams that cost taxpayers billions. Remind Mullin to just say NO to earmarks.”

The Oklahoma primary is set for June 26; the filing deadline for candidates to make the 2018 ballot in the state is April 13 — just two months away. The 2nd District, covering Eastern Oklahoma, leans Republican, and is a safe bet to remain in GOP hands regardless of the nominee.

Mullin, 40, was elected to Congress in 2012. The Club for Growth has a history of targeting Republicans in safe districts when they regard the incumbent as insufficiently conservative on fiscal issues.