Getty Images/Newscom

ABC News' Michael Falcone reports:

The Koch Brothers-funded conservative group, Americans For Prosperity, plans to official unveil its largest ad buy of the 2012 election cycle on Tuesday.

The massive anti-Obama ad buy starts on Wednesday in 11 states: Colorado, Florida, Iowa, Minnesota, Nevada, New Mexico, North Carolina, Ohio, Pennsylvania, Virginia, and Wisconsin.

Over the next three weeks, Americans For Prosperity will be rotating different ads and messages, and the first ad focuses on the national debt, according to a source familiar with the ad campaign.

Get more pure politics at ABC News.com/Politics and a lighter take on the news at OTUSNews.com

"President Obama pledged to cut the deficit in half, but we've gone $5 trillion deeper in debt under his watch," according to the group. "It's time to hold Obama accountable for his promises."

The initial ad features a national debt clock running ever higher alongside a Feb. 2009 interview with President Obama in which he says, "I will be held accountable. If I don't have this done in three years, then there's going to be a one-term proposition."

(Obama was talking about fixing the economy overall, not just reducing the deficit).

During the first week of the ad buy alone - Aug. 8 through Aug. 14 - the group will spend approximately $7 million, and the total advertising campaign should come to $25 to $27 million for both the television ads as well as an online component.

The group has already spent more than $17 million against President Obama so far this election cycle.