NASHVILLE (AP) — The Koch network has launched a $2 million TV and digital advertising attack against Democrat Phil Bredesen in Tennessee's U.S. Senate race.

Americans for Prosperity-Tennessee announced the ad Wednesday. The group supports Bredesen's opponent, Republican Congresswoman Marsha Blackburn.

The ad says Bredesen supported higher taxes while governor, mentioning gas and sales taxes. Under Bredesen, gas taxes and general sales tax didn't increase.

It says Bredesen used $9 million in taxpayer money on governor's mansion upgrades amid a recession and $4 million on an underground meeting hall labeled a "party cave." Bredesen never lived at the mansion, but held official events there.

Bredesen's campaign mentions he didn't create an income tax, but helped raise the tobacco tax to fund education and closed corporate tax loopholes.

In a digital ad, Bredesen responded that he'd rather discuss ideas.