WASHINGTON — President Donald Trump said from his hospital room on Saturday that he felt “much better” but the next few days will be “the real test” of his treatment for coronavirus disease 2019 (COVID-19), capping a day of contradictory messages from the White House about his condition.

In a four-minute video posted on Twitter, Mr. Trump, looking tired and wearing a jacket and open-necked shirt, said he “wasn’t feeling so well” when he first arrived at Walter Reed National Military Medical Center on Friday.

“Over the next period of a few days, I guess that’s the real test, so we’ll be seeing what happens over those next couple of days,” Mr. Trump said, seated at a round table in front of an American flag.

The remarks came hours after differing assessments of his health from administration officials left it unclear how ill the president had become since he tested positive for COVID-19 on Thursday night, a matter of enormous public concern.

A White House team of doctors said on Saturday morning that Mr. Trump’s condition was improving and that he was already talking about returning to the White House. One doctor said Trump told them, ‘I feel like I could walk out of here today.’

Within minutes, White House chief of staff Mark Meadows gave reporters a less rosy assessment, telling them, “The president’s vitals over the last 24 hours were very concerning and the next 48 hours will be critical in terms of his care. We’re still not on a clear path to a full recovery.”

Mr. Meadows, whose initial comments were delivered on condition that he not be identified, altered his tone hours later, telling Reuters that Mr. Trump was doing “very well” and that “doctors are very pleased with his vital signs.”

Mr. Meadows did not clarify the discrepancy in his comments. A Trump adviser who spoke on condition of anonymity said the president was not happy to learn of Mr. Meadows’ initial remarks.

Administration officials have described the move to Walter Reed as precautionary and said Mr. Trump would stay at the hospital for several days.

Another source who was briefed on Mr. Trump’s condition said the president was given supplemental oxygen before he went to the hospital. The decision to hospitalize Trump came after he had experienced difficulty breathing and his oxygen level dropped, according to a source familiar with the situation.

White House doctor Sean P. Conley told reporters outside the hospital on Saturday that Trump had not had trouble breathing, and was not given oxygen at Walter Reed.

He declined to give a timetable for Trump’s possible release from the hospital, and later had to issue a statement saying he misspoke after appearing to suggest Trump had been diagnosed as early as Wednesday.

“Today’s spectacle — doctors saying one thing, White House sources saying another thing, and both later amending their statements — only reinforces the credibility problems of this administration,” said Kyle Kondik, a political analyst at the University of Virginia’s Center for Politics.

CAMPAIGN UPENDED
The diagnosis was the latest setback for the Republican president, who is trailing Democratic rival Joe Biden in opinion polls ahead of the Nov. 3 presidential election.

With Mr. Trump in the hospital, his campaign announced “Operation MAGA,” based on his slogan “Make America Great Again,” which will see high-profile allies including Vice President Mike Pence and Mr. Trump’s elder sons, Donald Jr. and Eric, take over in-person campaigning starting next week.

Mr. Pence, who tested negative on Friday, is scheduled to debate Democratic vice presidential nominee Kamala Harris on Wednesday.

Mr. Biden, who largely avoided direct criticism of Mr. Trump during a campaign trip to Michigan on Friday, took a more aggressive tone on Saturday while speaking to a transit workers’ union on Saturday, even as he wished the president well.

“I’m in a little bit of a spot here, because I don’t want to be attacking the president and the first lady now,” Mr. Biden said, adding he hoped the Trumps make a full recovery.

But he quickly pivoted to Mr. Trump’s response to the pandemic, calling it “unconscionable” and blasting Mr. Trump’s comment in an interview this summer that “it is what it is” when asked about the death toll.

“I find this one of the most despicable things that I’ve encountered in my whole career,” Mr. Biden said.

Mr. Biden, who tested negative on Friday, told reporters he would next be tested on Sunday. His campaign will begin releasing the results of each test, a spokesman said. — Reuters