In this Aug. 30, 2013, file photo, Americans for Prosperity Foundation Chairman David Koch speaks in Orlando, Fla. (AP Photo/Phelan M. Ebenhack, File)

A conservative super PAC backed by the powerful political network of the billionaire industrialist Koch brothers is launching a new round of ads in two key Senate races and three competitive House contests. Together, the group is spending nearly $4 million to air the commercials.

Freedom Partners Action Fund is launching ads hitting Democrats in the Arkansas and Colorado Senate races; Florida's 26th and 2nd congressional districts; and West Virginia's 3rd district. All but Florida's 2nd district are currently controlled by Democrats.

The ads, which have been viewed by The Washington Post, aim to tie Democratic candidates to President Obama and his policies.

The commercial airing in the Colorado Senate race claims Sen. Mark Udall (D) is trying to conceal his record on energy. The Arkansas ad says Sen. Mark Pryor (D) voted with Obama "90 percent" of the time.

The ad in Florida's 2nd district is the only one that mentions the Republican candidate. Rep. Steve Southerland (R) is one of the most vulnerable House Republicans in the country. He faces Democratic challenger Gwen Graham. The ad praises Southerland and slams Graham.

The other two ads slam Reps. Nick Rahall (D-W.Va.) and Joe Garcia (D-Fla.).

Freedom Partners Action Fund reportedly plans to spend more than $15 million on the midterm elections.