BATON ROUGE (AP) — The name of former Ku Klux Klan leader David Duke has appeared in the race for Baton Rouge’s open congressional seat, in an advertisement attacking candidate Woody Jenkins.

The radio ad by Jenkins’ rival, fellow Republican Paul Sawyer, seeks to remind listeners of a federal fine levied against Jenkins six years ago for illegally concealing his purchase of a phone bank tied to Duke. The ad says Jenkins paid Duke $82,000 — an assertion Jenkins disputes.

In the ad, a voice says: ‘‘Would you pay David Duke $82,000? Would you want a congressman who did?’’

Jenkins, in an interview Wednesday with The Associated Press, said the ad was false, and called Duke a political enemy. Jenkins said his campaign purchased the phone bank through a third party, not knowing some of the money would go to Duke.

‘‘I certainly wouldn’t have paid money to that firm if I had known it would have gone to David Duke,’’ Jenkins said. ‘‘We never paid David Duke one cent.’’

The Federal Elections Commission fined Jenkins $3,000 in 2002 for concealing $82,500 in payments for the phone bank, operated by a company called Impact Mail Ltd., during his 1996 U.S. Senate runoff against Democrat Mary Landrieu of New Orleans. Jenkins narrowly lost that runoff; Duke finished fourth in the primary.

The transactions came to light in 1999, when a federal grand jury investigated Duke’s finances. The probe revealed that Duke had sold a voter mailing list for $150,000 in 1995 to Mike Foster, then in his first bid for governor. Jenkins then bought the use of Duke’s phone bank for his runoff against Landrieu.

Sawyer said he believes Jenkins ‘‘had an illegal business relationship with David Duke and tried to cover it up.’’

Jenkins and Sawyer are two of four in the GOP primary, hoping to fill the seat left open by the retirement of longtime incumbent Richard Baker, a Republican who left Congress for a private sector job.

Jenkins is a former state lawmaker who publishes community newspapers in the Baton Rouge area. Sawyer is a former aide to Baker who worked on Gov. Bobby Jindal’s transition team. Both are from Baton Rouge.

The other Republicans are businesswoman Laurinda Calongne, of Baton Rouge; and U.S. Navy veteran Michael Cloonan, of Slaughter.

Five Democrats are running: Andy Kopplin, former head of the Louisiana Recovery Authority; Rep. Michael Jackson of Baton Rouge; Joe Delatte, a construction worker from Zachary; Baton Rouge lawyer Jason DeCuir; and Rep. Don Cazayoux of New Roads.

Independent and third-party candidates are Peter Aranyosi of Hammond, Ashley Casey of Baton Rouge and Randall Hayes of Winnfield.

Party runoffs will be held April 5, if necessary. The general election is May 3.

The congressional district includes eight parishes: East Baton Rouge, Livingston, St. Helena, Pointe Coupee, West Baton Rouge, Iberville, East Feliciana and West Feliciana.

Duke, a former state representative, was most recently in the news in 2006, for attending a conference of Holocaust deniers in Iran.