The Senate Majority PAC is launching a major ad buy to back Sen. Mary LandrieuMary LandrieuFive unanswered questions after Trump's upset victory Pavlich: O’Keefe a true journalist Trump’s implosion could cost GOP in Louisiana Senate race MORE (D-La.), a group spokesman confirms to The Hill.

The group is spending $250,000 on an ad for Landrieu, who's facing a tough reelection campaign in the deeply conservative state. The ad will be rolled out on Friday and is the group's first in the state this election cycle.

The buy is the second major investment from the group in recent days — they're already on the air in North Carolina defending Sen. Kay Hagan (D-N.C.) and attacking her most likely opponent on ObamaCare. Both states are top GOP targets this election cycle, and have seen heavy advertising from outside conservative groups.

Landrieu launched her own debut ad on Wednesday that touted her work to change part of ObamaCare.