Donald Trump said he and his wife Melania would begin a “quarantine process” after Hope Hicks, one of the US president’s closest advisers, tested positive for coronavirus.

“Hope Hicks, who has been working so hard without even taking a small break, has just tested positive for Covid 19. Terrible!” Mr Trump tweeted on Thursday night. “The First Lady and I are waiting for our test results. In the meantime, we will begin our quarantine process!”

Ms Hicks, one of Mr Trump’s closest advisers, had travelled with Mr Trump to the first presidential debate in Cleveland, Ohio, on Tuesday night and to a campaign rally in Minnesota the following day.

In a television interview with Fox News host Sean Hannity, Mr Trump appeared to suggest that Ms Hicks may have contracted the virus due to her interactions with “soldiers and law enforcement” who would “come up to her”.

“She’s a very warm person,” Mr Trump said, adding: “It’s very, very hard.”

Mr Trump said he and Mrs Trump had been tested for coronavirus and were awaiting the results. “We’ll see what happens, who knows?” Mr Trump said. “I spend a lot of time with Hope. So does the First Lady.”

Ms Hicks, 31, returned to the White House in February 2020 as counsellor to Mr Trump after a two year hiatus in which she served as chief communications officer at Fox Corporation.

A former employee of Ivanka Trump’s fashion brand, Ms Hicks became Mr Trump’s press secretary for his 2016 presidential campaign.

After Mr Trump won the election, she joined the White House, where she rose to communications director and served as Mr Trump’s unofficial gatekeeper. Ms Hicks left the White House in 2018 during Robert Mueller’s investigation into Russian interference in the 2016 election, in which she was a person of interest.

Over the course of the pandemic, Mr Trump has downplayed the effectiveness of masks, suggesting that wearing them made some people, such as waiters, more likely to transfer the disease.

The president has also mocked Joe Biden for wearing one.

“Every time you see him, he’s got a mask,” Mr Trump said of his Democratic opponent. “He could be speaking 200 feet away from them and he shows up with the biggest mask I’ve ever seen.”

Despite the pandemic, the president has continued to hold large rallies across the country with many of those in the audience declining to wear masks or face coverings. After an indoor Trump rally in Tulsa, Oklahoma this summer, Herman Cain — the former candidate for the Republican presidential nomination — contracted coronavirus and died.

As of Thursday, Mr Trump was scheduled to host a rally in Florida on Friday night followed by two rallies in Wisconsin on Saturday.