North Carolina House Speaker Thom Tillis (R) slammed Sen. Kay HaganKay Ruthven HaganWarning signs flash for Tillis in North Carolina Tillis trails Democratic challenger by 7 points in North Carolina poll North Carolina businessman will challenge Tillis in GOP primary MORE (D-N.C.) for missing hearings focused on the threat of ISIS, saying she "failed to do her job" in a Wednesday conference call.

"She skipped per half the Armed Services Committee hearings over the last two years," Tillis said. "There is nothing more important than receiving briefs on national security. It's the top responsibility of every member of Congress. Senator Hagan has failed to do her job. What's her excuse for not showing up to work over half the time?"

Tillis said Hagan needs to be "held accountable for the fact that that she decided that there was something more important than the safety and security of this nation."

Hagan admitted after Tuesday night's debate that she'd missed an Armed Services Committee hearing on ISIS in order to attend a fundraiser, comments Republicans are arguing could be a game-changer in a race where she's long held a small lead in the polls.

Tillis has also taken heat about missing official business in order to fundraise — something a number of reporters pressed him on during the call.

He argued he'd had a better attendance record overall — and that Hagan had missed more important meetings than the ones he'd skipped.

"My attendance record and the productivity of the legislature is not what's being voted on in November. It's about keeping our nation safe and secure," he said.

"The one place Senator Hagan doesn't want to go is how often I showed up for work versus how often she has," he continued. "If I had anything approaching the seriousness of the threat of ISIS I would have canceled anything I was doing and in fact I did come back in Raleigh the vast majority of the time negotiating a budget and fulfilling the promises we made in North Carolina."

Hagan's campaign fired back, pointing to a Charlotte Observer editorial calling for Tillis to resign because he missed votes last year.

"Speaker Tillis is desperate to make North Carolinians forget that his hometown paper called on him to resign because he skipped work so much to fundraise," Hagan spokeswoman Sadie Weiner said. "In last night's debate, Kay was once again clear on how we take out ISIS, but Speaker Tillis won't even tell our servicemembers and their families if he would put boots on the ground. He will do anything to keep voters from knowing about his record and his positions on the issues. "