(CNN) -- The Democratic Senatorial Campaign Committee is releasing a new television ad in North Carolina on Thursday targeting Republican Thom Tillis' ties to billionaire conservatives Charles and David Koch.
The new 30-second spot will run statewide, and is part of a $9.1 million buy the DSCC has launched to protect incumbent Democrat Kay Hagan in one of the key Senate battlegrounds this cycle that could ultimately determine which party holds the majority in the chamber next year. The GOP needs to gain six seats in order to win control of the Senate in November.
The ad charges the Kochs with laying off 100 North Carolina workers and "spending millions" to elect Tillis "because they know he'll be another vote supporting tax breaks for companies like theirs that outsource North Carolina jobs."
"Letting our jobs go overseas. Another reason North Carolina can't trust Thom Tillis," says the ad's narrator.
Tillis himself went after Hagan in his own ad Thursday, calling out the incumbent senator for missing hearings related to terrorist threats in order to attend a fundraiser.
A CNN/ORC International survey released in late September showed Hagan leading Tillis 46 percent to 43 percent, with Libertarian Sean Haugh receiving the support of 7 percent of likely voters.
The Koch Brothers have been a constant presence in the Tar Heel State contest, with the brothers' grassroots organization Americans for Prosperity bombarding Hagan with more than $8 million in ads this cycle. AFP has attacked Hagan on a wide swath of issues from being a rubber stamp to Obama's agenda to accusing her of improperly benefiting from stimulus funds.
Hagan told MSNBC in February that North Carolina voters would not let the Koch brothers "buy this seat."