Mississippi state Sen. Chris McDaniel is scheduled to announce on Thursday whether he will challenge six-term Sen. Thad Cochran in the GOP primary, according to invitations to the event from local tea party groups.

“Mississippi state senator Chris McDaniel, a favorite of many Mississippi for Liberty and Tea Party members, stated just minutes ago that he plans to make an important announcement regarding his future political aspirations this coming Thursday, October 17th,” wrote Mississippi for Liberty’s Jim Cunningham to supporters, according to an email obtained by CQ Roll Call.

Another organization, the Mississippi Tea Party, sent out a similar invitation for the Ellisville, Miss., event. The Clarion-Ledger, which first reported the news of the impending announcement, notes that a third organization, the South Mississippi Tea Party, is chartering buses to take supporters to the announcement.

McDaniel did not return a phone message on Tuesday. But in an interview with CQ Roll Call last month, McDaniel would not rule out a challenge to either Cochran or Republican Rep. Steven M. Palazzo.

It is not certain that Cochran will run for re-election in 2014. He has told reporters several times that he is undecided about seeking another term.