COLUMBUS, Ohio (AP) — Donald Trump’s campaign is denouncing and severing ties with Ohio Republican Party Chairman Matt Borges.

It’s the latest crack in GOP unity in a critical battleground state where Republican Gov. John Kasich isn’t supporting the party’s presidential nominee. Borges has been openly critical of Trump on several occasions and has told some Ohio news outlets he wasn’t sure if he’d vote for Trump.

Trump Ohio chairman Bob Paduchik is accusing Borges of undermining Trump as part of a bid to be the next Republican National Committee chair. Borges has been mentioned as a possible successor to the current chair, Reince Priebus.

Paduchik says in a letter to state committee members that Trump is “very disappointed in Matt’s duplicity.”

Borges did not immediately respond to a request for comment.