A new campaign ad from Louisiana Sen. Mary Landrieu is drawing criticism from some conservative groups for using re-enactments of statements that the senator made in an Energy Committee hearing last year.

But Landrieu's campaign is defending the re-enactments as necessary to avoid breaking rules that forbid the use of footage shot by Senate cameras.

"It is against Senate ethics rules to use footage that was shot using Senate cameras in campaign ads," Landrieu campaign manager Adam Sullivan told ABC News.

The $250,000 ad buy began hitting Louisiana airwaves today and casts Landrieu, now the chair of the Senate Energy Committee, as a defender of Louisiana's oil and gas industry who has shown independence from President Obama.

"When we were cheated out of oil royalties," a voiceover in the ad says, portraying Louisianans watching Landrieu on television, before cutting to a re-enacted clip of an actual statement (occurs at 2:32 in video) that Landrieu made in the Energy Committee last year.

"They have to sit here and listen to the federal government say, 'We can't share a penny with you,'" Landrieu says. "I will not rest until this injustice is fixed."

"You think there are a bunch of fairy god mothers out there that just wave a magic wand?" Landrieu asks in another clip from the re-enacted Senate hearing.

Watch Landrieu's ad:

The conservative opinion magazine "The Weekly Standard" first reported that "the video clip doesn't come from C-SPAN or any other real TV," and the Republican opposition research super-PAC, America Rising, posted a video that juxtaposes Landrieu's re-enacted statement from the ad with the real statements from the hearing. The video used in America Rising's clip was shot originally by Senate cameras, which according to a Senate Resolution 431, prohibits it from being used for campaign purposes.

But American Rising Executive Director Tim Miller said that doesn't serve as justification for re-enacting the hearing.

"There is no rule that requires their campaign to manufacture a fake news show to cover a staged hearing," Miller said. "The ad is misleading to voters who are made to think they are looking at real news footage. It is telling that Sen. Landrieu is so desperate for positive news to use in an ad that she needed to fabricate it."

Watch America Rising's video:

As she campaigns for a fourth term in the Senate, Landrieu is considered one of the Senate's most vulnerable Democrats and has been weathering a storm of negative attack ads from conservative advocacy groups, such as the Koch Brothers-backed Americans for Prosperity and Freedom Partners. Landrieu, the only Democrat holding a statewide elected office in Louisiana, is facing off against Republican Rep. Bill Cassidy, as well as tea party candidate Rob Maness, in November's election.

ABC News' Arlette Saenz contributed to this report.