Milton Wolf, a distant cousin of President Obama, plans to make a "major announcement" Tuesday following months of speculation he'll launch a primary challenge to Sen. Pat RobertsCharles (Pat) Patrick RobertsModerates need to hold firm against radical right on Farm Bill GOP senators introduce bill to prevent family separations at border Senate GOP tries to defuse Trump border crisis MORE (R-Kan.).

Wolf, 42, said Monday he'll hold an event Tuesday evening at The Ritz Charles hotel in Overland Park, Kan., concerning the 2014 Senate race.

"The announcement will be in relation to recent speculation regarding the US Senate race in Kansas," according to a press release in his name. 

Earlier reports indicated Wolf, who is active in conservative Republican politics in Kansas and nationally, was considering challenging Roberts, who is seeking a fourth term in 2014.

In August, Wolf emailed Republican activists asking them to contact him if they wanted to help "save America from our failed political class."

Though Monday's message did not specify Wolf's plans, multiple posts on social media hint at a campaign for the Republican nomination.

"If you agree that the Washington career politicians of both parties are failing America, then join us Tuesday evening in Overland Park!" Wolf, a physician, wrote in a post in a Facebook post about the Tuesday event.

"Washington will never listen to us until we make them. Together, we can do this! See you on Tuesday!"

Wolf is Obama's second cousin once removed. He is related to Obama through the president's great-great grandfather, Thomas Creekmore McCurry.

Roberts, who was first elected to the Senate in 1996, won his 2008 election with 60 percent of the vote.

Roberts isn't typically the target of conservative attacks — he typically scores well on conservative scorecards from the Club for Growth and Heritage Action — but a statement released by his campaign on Monday indicated he's taking Wolf's potential bid seriously.

Leroy Towns, Roberts's executive campaign manager, noted that the senator has the support of a wide range of Kansas Republicans, including all statewide elected officeholders. He charged that "Dr. Wolf's attacks on Senator Roberts are attacks on those Kansas Republicans as well."

"If he becomes a candidate, Dr. Wolf will have many questions to answer regarding his position on those issues. Because he is unknown to most Kansas Republicans, he also will need to answer important questions regarding his qualifications, his medical business, including patient privacy issues and the extent his business relies in government payments," Towns warned.

And he added that "only a Johnson County doctor who is seriously out of touch with grassroots Republicans across the great state of Kansas would choose to announce his candidacy for statewide office with a glitzy party at the Ritz."

— Updated at 4:25 p.m. and 5:17 p.m.