The House Ethics Committee on Thursday warned Rep. Duncan D. Hunter not to vote on the House floor, two days after the California Republican pleaded guilty to misusing campaign funds.

In a sternly worded letter, the top two lawmakers on the committee noted that their request is not mandatory. But they told Hunter that he could face disciplinary action if he ignores their warning.

“This provision of House Rules was promulgated to preserve public confidence in the legislative process when a sitting Member of Congress has been convicted of a serious crime,” the committee’s chairman, Rep. Ted Deutch (D-Fla.), and ranking Republican member, Rep. Kenny Marchant (Tex.), said in the letter.

“Although, as the relevant legislative history indicates, this provision is not mandatory, we emphasize in the strongest possible terms that if you violate the clear principles of this provision ... you risk subjecting yourself to action by this Committee, and by the House, in addition to any other disciplinary action that may be initiated in connection with your criminal conviction,” they said.

Hunter last voted on Wednesday, when he voted against two procedural motions and for the passage of a bipartisan measure aimed at combating robocalls. He did not participate in House votes Thursday afternoon.

A spokesman for Hunter did not immediately respond to a request for comment.

The warning from the House Ethics Committee comes after Hunter pleaded guilty on Tuesday to one count of misusing campaign funds. He had previously pleaded not guilty.

The lawmaker and his wife, Margaret Hunter, were charged last summer with using more than $250,000 in campaign funds to pay for personal expenses including family vacations, theater tickets and school tuition.

In June, Margaret Hunter pleaded guilty to one count of conspiring with her husband to spend $25,000 in campaign funds for personal use. As part of the deal, she agreed to cooperate with prosecutors and testify against her husband.

“Whatever my time in custody is, I will take that hit,” Duncan Hunter said in a TV interview that aired Monday. “My only hope is that the judge does not sentence my wife to jail. I think my kids need a mom in the home.”