Among the precautions Stepien encouraged were the wearing of masks, washing hands, practicing social distancing, and working from home when a staffer feels ill.

He also reminded staffers to conduct daily check-ins on an app the campaign’s human resources department requires them to use to monitor symptoms and allow for contact tracing.

Trump’s diagnosis, announced via Twitter shortly before 1 a.m., came just over a month away from Election Day. It potentially scrambles his campaign schedule and closing message in the critical final weeks before voters head to the polls, and as early voting for a number of additional states kicks off.

It’s unclear when or how the president and first lady contracted the virus, which has infected more than seven million Americans and killed more than 207,000.

One of Trump’s closest aides, senior counselor Hope Hicks, tested positive for the virus earlier in the week, and had traveled with Trump and a coterie of other advisers to the first presidential debate Tuesday night and a campaign rally in Minnesota with hundreds of attendees.

White House chief of staff Mark Meadows declined to discuss a timeline of the president’s diagnosis with reporters Friday morning.

A senior Trump campaign official said that there was an all-staff meeting planned for Friday morning at the campaign’s northern Virginia headquarters that Stepien canceled via email just before 11 p.m. on Thursday. The source was unsure if the cancellation was related to Trump’s diagnosis, but acknowledged that, in hindsight, it appeared odd.

"I remember when I saw that, I was like 'C'mon guys. We've got 32 days left,'" the source said, adding that some staffers “are kind of like, ‘What now? What does this mean for what we're trying to do here with 32 days left?'"

"I don't want to say this hit us by surprise because we knew the risks,” the source also said. But Trump “wanted to campaign and be out there with the people, so we tailored the campaign to the president's wishes. This definitely changes our plans though.”

While Stepien noted that “some public events will be taken down,” he assured staffers that “the campaign office remains open and our nation-wide team will continue with our efforts to re-elect President Trump.”

Trump was set to hold two rallies in Wisconsin on Saturday, and prior to his diagnosis was set to attend a roundtable with supporters and hold a rally in Florida on Friday.