Stephen Miller, a top Trump aide, tests positive for the virus.

On Tuesday evening, senior administration officials confirmed that Stephen Miller, Mr. Trump’s top speechwriter and a policy adviser, had tested positive for the coronavirus, joining a growing list of Mr. Trump’s close aides who have the virus.

“Over the last five days I have been working remotely and self-isolating, testing negative every day through yesterday,” Mr. Miller said in a statement. “Today, I tested positive for Covid-19 and am in quarantine.”

Mr. Miller is married to Katie Miller, Vice President Mike Pence’s communications director. A senior administration official said Ms. Miller, who contracted the virus this spring and returned to work in May, was tested Tuesday morning and was negative for any new infection.

On Tuesday, many White House offices were empty as officials stayed home to wait out the infectious period from an outbreak of the coronavirus within the building and among people who had been there.