The United States Office of Government Ethics on Tuesday urged the White House to discipline presidential advisor Kellyanne Conway for advertising on television the clothing brand belonging to President Donald Trump's daughter, Ivanka Trump.

"There is strong reason to believe that Ms. Conway has violated the Standards of Conduct and that disciplinary action is warranted," the director of the organization, Walter Shaub, wrote in a letter to the White House.

Two weeks ago, luxury department store chain Nordstrom withdrew Ivanka's line of clothing from its stores over a drop in sales in recent months, a move interpreted by the president as a personal attack.

Go buy Ivanka's stuff. It's a wonderful line. I own some of it

During an interview with Fox News, Conway gave a "free commercial" for the Ivanka Trump brand, according the advisor herself.

"Go buy Ivanka's stuff. It's a wonderful line. I own some of it," Conway said.

Conway's comments substantially sparked a controversy in the country, and the chairman of the US House Committee on Oversight and Government Reform, Republican Jason Chaffetz, and the highest-ranking Democrat of the body, Elijah Cummings, have requested the OGE review the case.

White House spokesman Sean Spicer said Conway was "counseled" following her statements to Fox News, but no concrete measures have been enforced.