Donald Trump's chief of staff Mark Meadows has been diagnosed with COVID-19.
Two senior administration officials told The Associated Press that Mr Meadows had tested positive for the virus.
Mr Meadows travelled with the president in the lead-up to 3 November.
His last public appearance was early Wednesday morning as Mr Trump falsely declared victory in the vote count. He was not wearing a mask at the time.
It was not immediately clear when or how Mr Meadows was infected.
His diagnosis was revealed after the United States set another daily record of coronavirus infections, with 128,000 new cases in the last 24 hours.
Several senior Trump administration officials have contracted the virus in recent weeks, including the Mr Trump and his wife Melania.
Press Secretary Kayleigh McEnany and policy advisers Stephen Miller and Hope Hicks are among more than a dozen other senior White House figures to be infected with since the start of October.
The United States has been hit harder than any other country by the COVID-19 pandemic since it swept the world at the start of this year.
More than 9.7 million people have contracted the virus nationwide, with more than 236,000 dead.
- With AFP
