Ms. Holland was appointed by Democratic Gov. Brad Henry following the resignation of Democratic Insurance Commissioner Carroll Fisher in the wake of corruption charges.

Ms. Holland faces State Rep. Bill Case, R-Midwest City, on the GOP ticket. He has denied any connection with the ad and has pledged to run an issues-based campaign.

Mr. Case has said that Ms. Holland lacks qualifications for the position, and he has promised to "erase the gray cloud hanging over the office."

In a letter to supporters, Ms. Holland decried the ad as an out-of-state project run by people who reside in Texas and New Hampshire.

"Oklahomans deserve better than this. They deserve to know that I have been cleaning up the insurance department, and that we've recovered more than $25 million for Oklahomans through fraud and enforcement actions, and that we are holding the insurance industry fully accountable to their policyholders," she wrote.

Marilyn Hughes, executive director of the Oklahoma Ethics Commission, said the group behind the controversial ads has yet to file any campaign contribution statement.

The group maintains that they are not required to since no name is mentioned.

Ms. Hughes said that it was her personal opinion that the candidate was identified clearly enough to have to file such statements.

But it will be up to the full board to make that determination and it does not meet until after the election, she said.