SAN DIEGO — U.S. Rep. Duncan Hunter, R-Calif., announced Friday he plans to resign from Congress "shortly after the holidays," just days after admitting to misusing campaign funds.

Hunter pleaded guilty in federal court Tuesday to one count of conspiracy to misuse campaign funds after prosecutors said he and his wife, Margaret, who pleaded guilty earlier this year to conspiracy to misuse campaign funds and was expected to testify against him, "converted and stole" more than a quarter-million dollars in campaign funds.

"Shortly after the Holidays I will resign from Congress," Hunter said in a brief statement. "It has been an honor to serve the people of California’s 50th District, and I greatly appreciate the trust they have put in me over these last 11 years."

The announcement came one day after the House Ethics Committee warned him that he "should refrain from voting" on the House floor following his plea.

The case against Hunter included documentation of campaign cash being used for family trips to Hawaii and Italy, plane rides for relatives and alleged romantic flings with lobbyists and congressional aides.

The district, one of few remaining Republican big city congressional districts between Los Angeles and the border, overlapped with a since-redrawn district represented by his namesake father for nearly three decades.

Hunter's resignation target of around January means Calif. Gov. Gavin Newsom can leave the seat vacant until after the Nov. 2020 general election, call for a special election, or consolidate a special election with the March primary.

Hunter faces up to five years behind bars when he's sentenced in March.

Following his indictment last year, Hunter argued he was the victim of a political witch hunt. But on Tuesday he said, "I failed to monitor and account for my campaign spending. I made mistakes."

Dennis Romero reported from San Diego and Alex Moe from Washington, D.C.