MEXICO CITY >> Mexico’s president acknowledged Wednesday he did “briefly faint” over the weekend before he was diagnosed with COVID-19, something his spokesman had previously denied.

President Andrés Manuel López Obrador said his doctors had been concerned enough to administer a liter of rehydration fluids. He said in a videotaped chat from the National Palace in Mexico City — where he lives and is isolating — that doctors wanted to fly him back to the capital in a stretcher.

López Obrador had been on a working tour of the Yucatan peninsula Sunday when he tested positive for the coronavirus, his third bout of COVID-19.

But he wrote in his social media accounts Sunday that “it isn’t serious.”

Reports in the local press that day said López Obrador had felt faint Sunday morning and had to cancel his tour, something his presidential spokesman denied at the time.

But on Wednesday, the president acknowledged that it “had become complicated … I had a crisis, because my blood pressure suddenly went down” during a meeting with military engineers working on his pet project, a tourist train on the Yucatan peninsula.

“It was like I fell asleep,” he said. “I didn’t lose consciousness, but I did briefly faint, because of the low blood pressure.”

The president said he was flown back to Mexico City aboard an “air ambulance,” but specified he was not carried in a stretcher.

López Obrador, 69, who has acknowledged a history of heart problems, said his heart was “not at all affected.”

On Tuesday, U.S. Ambassador Ken Salazar, who frequently meets with López Obrador, said he too had tested positive for COVID-19. He wrote in his Twitter account that “I am well.”

López Obrador caught COVID-19 in early 2021 and was ill, but recovered after receiving what he described at the time as an experimental treatment. In January 2022, he announced he had come down with COVID-19 a second time, amid a spike in coronavirus infections in Mexico.

López Obrador declined to enact mandatory mask mandates and he refused to wear a mask even at the peak of the pandemic unless it was absolutely necessary, as on airline flights. He famously refused to use Mexico’s presidential jet, which he recently announced had been sold to Tajikistan.

While López Obrador remains in isolation — he said he has spent the time working on speeches — Interior Secretary Adán Augusto López has been filling in at the daily presidential morning news briefings.

That could provide a boost for the interior secretary’s flagging campaign to win the presidential nomination of López Obrador’s Morena party for the 2024 elections. López, who is not related to the president, currently trails Mexico City Mayor Claudia Sheinbaum in most polls of the primary race.