U.S. first daughter Ivanka Trump's personal assistant has tested positive for the coronavirus, U.S. media reported Friday.

Citing an anonymous source, CNN reported that the assistant, who worked in personal capacity for Ivanka, has not been around the first daughter for weeks.

The news came on the same day when Vice President Mike Pence's spokesperson, Katie Miller, was confirmed to have been infected with the disease.

Amid concerns over the transmission of the contagious disease among senior administration officials, White House Press Secretary Kayleigh McEnany said at Friday's briefing that measures are in effect to keep the virus from spreading among staff.

Ivanka and her husband Jared Kushner, both of whom are President Donald Trump's senior advisers, tested negative for the virus.

Trump, who along with Pence also had negative tests Thursday, said Friday that he was not worried, adding that "strong precautions" had been taken in the White House. He told reporters Thursday that he would be tested for the coronavirus daily.