WASHINGTON, DC, United States — A top aide to US President Donald Trump on Sunday defended his colleague, Kellyanne Conway, after she was widely criticised for her public endorsement of the fashion line of Trump's daughter, Ivanka.

Speaking on the ABC's "This Week" program, White House aide Stephen Miller said Trump adviser Kellyanne Conway was making a "lighthearted, flippant" comment when she urged Americans to buy Ivanka Trump's products.

Conway's comments prompted criticism from both Republican and Democratic lawmakers, as well as some legal experts who said she may have violated ethics rules that prohibit using a public office to endorse products or advance personal business gains.

In comments to the Associated Press, Republican Jason Chaffetz, chairman of the House of Representatives Oversight committee, said Conway's statement was "clearly over the line, unacceptable."

By Julia Harte; editor: Alan Crosby.