Republican Sen. Jim Inhofe plans to announce soon that he will retire from Congress before his six-year term is up, triggering a special election this year in Oklahoma to pick his replacement, according to a person with direct knowledge of the senator's plans.

       Inhofe, 87, is expected to serve until the current session of Congress ends in January, the person said. He was elected to a fifth Senate term in 2020. The person spoke to The Associated Press on the condition of anonymity to discuss sensitive details.

       The timing of the announcement is related to an quirk in Oklahoma law that requires the governor to call a special election if a lawmaker announces they intend to retire before March 1. Inhofe's chief of staff is expected to run for the Senate seat and Inhofe is expected to support his candidacy, the person said.

       Republicans will be heavily favored to retain the seat, as Oklahoma hasn't sent a Democrat to the Senate since 1990.

       A longtime fixture in Oklahoma politics, Inhofe is the ranking Republican on the Senate Armed Services Committee. He first won the Senate seat in a special election in 1994 after then-Democratic Sen. David Boren stepped down to become president of the University of Oklahoma. Before that, Inhofe served in the Oklahoma House, Oklahoma Senate and three terms as Tulsa’s mayor before winning a seat in the U.S. House.

       Recommended Wintry weather disrupts travel across the heartland Ice likely in Southern Plains; New England to see heavy snow Texas law firm agrees to review Oklahoma death penalty case

       The senator’s office did not immediately return a request for comment.

       ___

       Associated Press writer Sean Murphy in Oklahoma City, Oklahoma, contributed.