White House Counselor Kellyanne Conway, center, at a White House media briefing. (Alex Wong/Getty Images)

The federal government’s top ethics official on Thursday chastised the White House for declining to discipline President Trump’s senior adviser Kellyanne Conway for her on-air endorsement of Ivanka Trump’s clothing line.

Walter M. Shaub Jr., director of the Office of Government Ethics, had urged officials last month to reprimand Conway after she told Fox News viewers to “go buy Ivanka’s stuff,” appearing to violate a federal rule banning public officials from using their position to endorse products or services.

But Stefan C. Passantino, who handles White House ethics issues as the president’s deputy counsel, rebuffed that recommendation, saying in a letter last week that Conway “acted inadvertently and is highly unlikely to do so again.”

Shaub on Thursday wrote Passantino that he remained concerned about Conway’s “misuse of position.”

“When an employee’s conduct violates [federal rules], disciplinary action serves to deter future misconduct,” Shaub wrote. “Not taking disciplinary action against a senior official under such circumstances risks undermining the ethics program.”

The exchange highlighted ongoing tensions between Shaub, who was appointed by President Barack Obama in 2013, and the White House over the intertwining of the Trump family’s private business interests and the president’s public duties. Shaub in January criticized Trump for choosing to retain ownership of his global real estate and branding company.

Shaub took issue with Passantino’s assertion last week that “many regulations” that fall under the ethics office do not apply to presidential staffers. “It is critical to the public’s faith in the integrity of government that White House employees be held to the same standard of ethical accountability as other executive branch employees,” Shaub wrote.

He also wrote to the chairman of the House Oversight Committee, Rep. Jason Chaffetz (R-Utah), and the panel’s top Democrat, Rep. Elijah E. Cummings (Md.), voicing concern that “the White House’s response makes clear that disciplinary action will not be taken.”

Cummings fired off a letter to White House Counsel Donald F. McGahn asking for an explanation of what federal rules the executive office has been counseled “do not apply to them.”

“The President’s staff need to follow ethics rules — not flout them,” Cummings wrote. “When they violate these rules, the President must impose discipline, not invent a legal fiction that these rules do not apply.”

Chaffetz, who previously called Conway’s remarks “absolutely wrong, wrong, wrong,” declined to comment. He said in a statement last week that “swift action was taken by this committee to highlight the problem with Ms. Conway’s comments,” and added that the committee would monitor the process “to ensure the administration understands these types of comments are inappropriate and takes meaningful steps to prevent future missteps.”

Conway and the White House did not immediately respond to requests for comment.

The ethics office does not have the power to investigate potential rule violations or enforce penalties. It can recommend disciplinary action, but its advice is nonbinding, and it cannot appeal a decision if the employee’s federal office — in Conway’s case, the White House — declines to take action.

Federal employees can face multiday suspensions, loss of pay or terminations for similar violations. U.S. Fish and Wildlife Service employees, for instance, face a minimum five-day suspension, while Customs and Border Protection employees can be suspended for 14 days for a first offense and removed from their position for a second violation.