President Donald Trump is showing symptoms of the novel coronavirus, but mild ones, according to two people familiar with his condition.

The president, who said early Friday that he had tested positive for the virus, has had what one person described as coldlike symptoms. At a fundraiser he attended at his golf club at Bedminster, N.J., on Thursday, where one attendee said the president came in contact with about 100 people, he seemed lethargic.

A person briefed on the matter said that Trump fell asleep at one point on Air Force One on the way back from a rally in Minnesota on Wednesday night.

A White House official said that as of Thursday night, the president’s treatment plan was still being discussed. So was a possible national address or a videotaped statement from the president to demonstrate that he was functioning and that the government is uninterrupted.

Trump, who for months has played down the seriousness of the virus and hours earlier Thursday night told an audience that “the end of the pandemic is in sight,” will quarantine in the White House for an unspecified period of time, forcing him to withdraw at least temporarily from the campaign trail only 32 days before the election Nov. 3.

Trailing in the polls, the president in recent weeks has increasingly held crowded campaign events in defiance of public health guidelines and sometimes state and local governments. When he accepted the nomination on the final day of the Republican National Convention, he invited more than 1,000 supporters to the South Lawn of the White House and has held a number of rallies around the country since, often with hundreds and even thousands of people jammed into tight spaces, many if not most without masks.

His dramatic disclosure came in a Twitter message just before 1 a.m. after a suspenseful evening following reports that Trump’s close adviser Hope Hicks had tested positive.

Gov. Philip D. Murphy of New Jersey urged people who attended Trump’s Bedminster fundraiser to get tested and said that the state was using contact tracing to try to find them.