WASHINGTON: The girlfriend of US President Donald Trump's eldest son has tested positive for COVID-19. Kimberly Guilfoyle, 51, is a former Fox News television personality.

She had recently traveled to South Dakota to see the US president's Fourth of July speech and celebration fireworks at Mount Rushmore. Guilfoyle is the third person close to the US president to test positive for the dreaded virus.

She was immediately isolated, according to an international daily. She underwent a routine virus test conducted on anyone expected to come in close contact with the President.

Sergio Gor, chief of staff to the Trump campaign's finance committee was quoted saying to the daily, "She's doing well, and will be retested to ensure the diagnosis is correct since she's asymptomatic."

As a precautionary measure, all her upcoming events have been cancelled.

Donald Trump junior has tested negative and but has gone for home isolation and cancelled all events, the daily reported.

Earlier, Trump's personal valet and the US vice president's press secretary also tested positive for the virus.

The US reported on Friday at least 51,842 new cases, marking the third day straight with a daily high of more than 50,000 cases, according to data from Johns Hopkins University.

The pandemic has claimed nearly 1,30,000 American lives and a recent resurgence "puts the entire country at risk," top infectious disease expert Anthony Fauci has said.