In a stunning tweet made just before 1 a.m. on Friday, President Donald Trump revealed that he and First Lady Melania Trump had tested positive for the coronavirus and will quarantine. [UPDATE] By Friday evening, the White House announced that Trump would be going to Walter Reed Medical Center "at the recommendation of his physician and medical experts" for a few days. [More details below]

The news came hours after he disclosed in an interview with Fox News that one of his top aides, Hope Hicks, had tested positive for the virus. Hicks had been traveling with the president, CNN reports, accompanying him to the first presidential debate in Cleveland on Tuesday, and seen boarding Marine One.

The president's physician said Trump should be able to carry out his duties "without disruption." But Trump is 74 years old, and weighing 243 pounds, he is considered to be at higher risk for developing severe symptoms from the virus. For critics, his infection is bound to be seen as a comeuppance. For months, the president has downplayed the severity of the pandemic, saying it would simply "go away" on its own. His insistence on holding mass rallies went against the advice of his own top health officials, who have urged Americans to socially distance and wear masks.

Trump has worn a mask on only a few occasions and at times mocked the practice.

Days earlier, during the presidential debate against Democratic nominee Joe Biden, Trump was asked why he typically appears in public without a mask. The president explained, "I think masks are okay... I put a mask on, you know, when I think I need it." He added, referring to Biden's conspicuous wearing of masks, "Every time you see him, he’s got a mask. He could be speaking 200 feet away from me, and he shows up with the biggest mask I’ve ever seen."

Public health experts all agree that mask-wearing and social distancing are key to mitigating the spread of the disease, which has afflicted over 7.2 million Americans, killing 207,816.

"Jill and I send our thoughts to President Trump and First Lady Melania Trump for a swift recovery. We will continue to pray for the health and safety of the president and his family," Biden Tweeted. Biden also said that he and his wife have tested negative for COVID-19 so far.

Hicks reportedly received her diagnosis before Trump and his team traveled to Bedminster, New Jersey for a fundraiser at a golf club. Trump was in close contact with "dozens of other people, including campaign supporters," according to the Washington Post.

Officials said the president did not wear a mask Thursday.

He was tested when he returned to Washington, D.C.

According to the NY Times, "During late-night conversations, aides to Mr. Trump were discussing whether he should give an address to the nation on Friday from the White House or find some other way for him to reassure the public. But the aides were still in a state of shock as they absorbed the news, and there was no immediate word on how far the infection may have spread among senior White House officials, who generally do not wear masks in deference to the president’s disdain for them."

Trump's management of the pandemic is considered one of the pivotol issues of the upcoming election. Critics and health experts have assailed him for not issuing sweeping federal guidelines for mask-wearing, and allowing and encouraging states to reopen businesses too early. His administration has reportedly pressured the CDC to downplay risks of the pandemic and tried to muzzle public health experts, like Dr. Anthony Fauci. Just last month, Trump said that the country was "rounding the corner" on the virus.

Other world leaders have contracted COVID: Jair Bolsonaro of Brazil and British Prime Minister Boris Johnson, who became so ill he was hospitalized and put on a ventilator.

Governor Andrew Cuomo, who has frequently criticized Trump's response to the pandemic and approach to government overall, said in a statement, "My thoughts are with President Trump and the First Lady and I wish them a full and speedy recovery. This virus is vicious and spreads easily. Wear a mask. Let's all look out for each other."

In his remarks at the Al Smith Dinner on Thursday night, Trump said, "I just want to say that the end of the pandemic is in sight, and next year will be one of the greatest years in the history of our country. "

Update: The president was scheduled to participate in a call with governors at 12:15 p.m. to discuss the coronavirus. Cuomo had said Trump was expected during the governor's 11:30 a.m. press call, but when during an interview at 1:10 p.m., Cuomo revealed that Pence took Trump's place.

According to Cuomo, Pence said that the president tested positive for COVID-19 and asked him to take his place during the call.

Trump's campaign announced that all scheduled events were either moving online or being postponed.

Update. 6:30 p.m.: Just after 5 p.m., the White House released a statement, “President Trump remains in good spirts, has mild symptoms, and has been working throughout the day. Out of an abundance of caution, and at the recommendation of his physician and medical experts, the President will be working from the presidential offices at Walter Reed for the next few days. President Trump appreciates the outpouring of support for both he and the First Lady."

Sources told media outlets that Trump has had a fever, and his doctor revealed in the afternoon that he gave the president Regeneron's experimental antibody cocktail that has had promising results, but only from 275 people in a study of 1,000. Experts have also said they need more data to understand the benefits.

The president's second son, Eric Trump, Tweeted that his father is a "true warrior. He will fight through this with the same strength and conviction that he uses to fight for America each and every day. I ask you to join me in praying for his recovery. I have never been more proud of someone and what they have had to endure."

Trump, wearing a mask, walked to Marine One for the flight to Walter Reed.