The 140 billboards warning residents of inner-city neighborhoods in Wisconsin and Ohio that they could go to jail for committing voter fraud are being taken down Monday. The move comes after the private family foundation funding them declined to make its identity known.

Civil rights groups criticized the ads as an attempt to intimidate voters in primarily low-income, minority neighborhoods by associating voting with jail time. The billboards show a large gavel and the text "Voter fraud is a felony! Up to 3 1/2 yrs & $10,000 Fine."

Clear Channel, the company that put up the advertisements, said the foundation funding the signs was mistakenly allowed to remain anonymous when it bought the billboards, a violation of the company's policy against accepting anonymous political ads.

"We reviewed the situation and in light of the fact that these billboards violate our policy of not accepting anonymous political ads, we asked the client how they would prefer to work with us to bring the boards into conformance with our policy," Clear Channel spokesman Jim Cullinan wrote in an email. "The client thought the best solution was to take the boards down, so we're in the process of removing them."

Cullinan would not comment about whether the foundation will still have to pay for its full contract, which asked for the billboards to run until Election Day, Nov. 6.

Republicans have led the controversial efforts to curb voter fraud this year, as Democrats argue that voter ID laws, tighter regulations on voter registration drives, and efforts to roll back early voting tend to depress turnout and hurt Democratic candidates. Civil rights groups argue that voter fraud is so rare—two recent elections have shown a fraud rate of 0.00004 percent—that it's not worth instating voter ID rules that could discourage legitimate voters.

Supporters of the laws argue that it makes sense to tighten the rules around voting to protect the integrity of elections.

The Cleveland Plain Dealer reports that 15 new billboards will go up this week in Cleveland that say, "Voting is a right, not a crime." Clear Channel will donate 10 of them, and the Cleveland City Council is financing the other five. The Lawyers' Committee for Civil Rights Under Law will also donate a few dozen billboards to run in Columbus and Cleveland that read, "Stand up and have your say—Vote. When we vote, we are all equal."