North Carolina's ad war is threatening to boil over as establishment Republicans' favored candidate seeks to quell attacks on his record.

North Carolina House Speaker Thom Tillis (R) is accusing Democrats of trying to defeat him in his primary so they can have a weaker opponent against Sen. Kay HaganKay HaganLinking repatriation to job creation Former Sen. Kay Hagan in ICU after being rushed to hospital GOP senator floats retiring over gridlock MORE (D-N.C.). And Democrats are gleefully piling on with accusations that he helped scandal-plagued staffers get more money as they resigned.

Tillis has a new ad that pushes back against claims from the Senate Majority PAC that he gave two staffers bonuses after they'd resigned following extramarital affairs. The ad calls those claims "false" and says he fired the two staffers, including a chief of staff he was rooming with at the time.

Tillis said in a statement that he'd accepted a staffer's resignation, not that he'd fired them.

"Seen those ads attacking Thom Tillis? They're false. Tillis fired the staffers. Know who's paying for those sleazy ads? It's Harry ReidHarry ReidThe Memo: Trump pulls off a stone-cold stunner The Memo: Ending DACA a risky move for Trump Manchin pressed from both sides in reelection fight MORE. Reid is trying to fool Republican voters, meddling in our primary to get a weak opponent for Kay Hagan," the ad says before saying Democrats fear Tillis the most.

Democrats are hoping Tillis loses his primary to one of two more conservative opponents, believing Hagan will have a better chance against one of them. Establishment Republicans are trying to push him through the early May primary and help him avoid a runoff; American Crossroads is spending more than $1 million airing ads on his behalf.

Democrats are responding later today with a conference call to dispute Tillis's claim that he fired the staff and calling for the ad to be taken down.

"Speaker Tillis's ad is so false his spokesman won't even repeat the claim contained in it, and he should direct his campaign to stop running it," Ben Ray, a spokesman for the Hagan-allied Forward North Carolina, tells The Hill. "The truth is, Tillis decided first that he wanted to pay taxpayer-funded severance to his scandalous staff, then worked to find a way to do it. Resignation, not firing for cause, is what he chose."

The original Senate Majority PAC ad, which is running in the state, says Tillis spent "our money to clean up his mess."