Senior White House adviser Kellyanne Conway drew sharp criticism and complaints on Thursday over the ethics of using her position to promote the clothing line of President Donald Trump's daughter Ivanka, one day after Trump attacked a retailer for dropping it.

Federal ethics rules prohibit executive branch employees from using their positions to endorse products or for the private gain of friends.

"Go buy Ivanka's stuff ... I'm going to go get some myself today," Conway told Fox News in an interview from the White House. "I'm going to give a free commercial here: Go buy it today, everybody."

Kellyanne Conway spruiking Ivanka Trump's brand on Fox News.

The non-profit Citizens for Responsibility and Ethics in Washington and Public Citizen filed complaints with the Office of Government Ethics (OGE) and the White House Counsel's Office.

"It's a violation of the rule," Norman Eisen, who served as an ethics adviser to Democratic President Barack Obama, told MSNBC. "It's a serious matter."