The Marine Corps has ordered U.S. Rep. Duncan Hunter, R-Calif., to stop using the Corps’ Eagle, Globe and Anchor and a trademarked phrase on his campaign mailers.

The Marine Corps Trademark Licensing Program office told Hunter that it his campaign was using the official Marine Corps emblem and the phrase “No Better Friend, No Worse Enemy” in “at least one fundraising mailer” to constituents.

“We thereby request your campaign immediately remove the Emblem and the Phrase from its mailers, and, without limitation, from all campaign materials including websites and other instances where the Emblem or the phrases are being used,” the letter reads.

The letter from the Marine Corps trademark office was obtained and first reported by NBC News.

A spokesperson for Hunter’s office told NBC News that it was complying with the Marine Corps’ request and taking “all appropriate measures” to address the issue.

The campaign mailer, according to NBC News, targets Democrat Ammar Campa-Najjar, who is running against Hunter in 2020, and two other Democratic congresswoman Reps. Ilhan Omar of Minnesota and Rashida Tlaib of Michigan by calling them “radical Democrats” who “want you to forget their anti-Semitism or family-terrorist ties!”

The phrase “No Better Friend, No Worse Enemy” was coined by former Secretary of Defense James Mattis when he commanded the 1st Marine Division during the invasion of Iraq in 2003.

That phrase is now a registered trademark of the Marine Corps.

The Corps’ trademark office said that Hunter’s use of the official Marine emblem and the trademarked phrase is “likely to convey the impression that the Marine Corps favors your candidacy over another, or ‘endorses’ your views on a particular issue, and is a use of which we cannot grant permission.”

Hunter is a Marine Corps veteran and is facing federal corruption charges. Hunter and his wife, Margaret, are accused of using more than $250,000 of campaign funds for personal expenses.

Hunter’s wife pleaded guilty in June to one corruption count.

A judge refused to dismiss corruption charges against Rep. Duncan Hunter in July.

The Corps’ trademark office told Hunter he could state he was a Marine veteran, provide information about his service “based on fact," or use a Marine veteran logo, which is used by Marines to "indicate their pride in service.”

The Associated Press contributed to this story.