MEXICO CITY -- Mexican President Andres Manuel Lopez Obrador said he has tested positive for COVID-19, an announcement that comes as his country registers the highest levels of infections and deaths to date.

Lopez Obrador, who has been criticized for his handling of Mexico's pandemic and for not setting an example of prevention in public, said Sunday on his official Twitter account that his symptoms are mild and he is under medical treatment.

"I regret to inform you that I am infected with COVID-19," he tweeted. "The symptoms are mild but I am already under medical treatment. As always, I am optimistic. We will all move forward."

Jose Luis Alomia Zegarra, Mexico's director of epidemiology, said the 67-year-old Lopez Obrador had a "light" case of COVID-19 and was "isolating at home."

Mexico's president wrote that while he recovered Interior Secretary Olga Sanchez Cordero would be taking over for him in his daily news conferences, at which he usually speaks for two hours without breaks each weekday.

Despite his age and high blood pressure, Lopez Obrador has not received a vaccine shot even though Mexico has already received a batch of Pfizer-BioNTech doses. He has said that health workers would be the first ones to get them. Under the government plan, people over 60 will start being vaccinated in February.

Lopez Obrador has rarely been seen wearing a mask and continued to keep up a busy travel schedule taking commercial flights.

He has also resisted locking down the economy, noting the devastating effect it would have on so many Mexicans who live day to day, despite that the country has registered nearly 150,000 COVID-19 deaths and more than 1.7 million infections. A new wave of infections has pushed the health system of the country's capital city close to saturation.

Early in the pandemic, asked how he was protecting Mexico, Lopez Obrador removed two religious amulets from his wallet and proudly showed them off.

"The protective shield is the `Get thee behind me, Satan,"' Lopez Obrador said, reading off the inscription on the amulet, "Stop, enemy, for the Heart of Jesus is with me.

In November, Tedros Adhanom Ghebreyesus, head of the World Health Organization, urged Mexico's leaders be serious about the coronavirus and set examples for its citizens, saying that "Mexico is in bad shape" with the pandemic.

He didn't name Lopez Obrador, but said: "We would like to ask Mexico to be very serious."

"We have said it in general, wearing a mask is important, hygiene is important and physical distancing is important and we expect leaders to be examples," he added.

At the start of the pandemic Lopez Obrador was criticized for still leaning into crowds and giving hugs. The eternal campaigner, Lopez Obrador's style of politics has always been very hands on and personal. As the pandemic grew he began limiting attendance to his events and maintaining his distance from supporters.

But on Friday, Lopez Obrador posted a photo of him, Foreign Minister Marcelo Ebrard, a translator and former chief of staff Alfonso Romo, all gathered around a table for a phone call with U.S. President Joe Biden. None were wearing masks; the foreign relations department has not answered questions about whether Ebrard has been tested.

Lopez Obrador's announcement came shortly after news emerged that he would speak with Russian President Vladimir Putin on Monday about obtaining doses of the Sputnik V COVID-19 vaccine.

Mexico Foreign Affairs Secretary Marcelo Ebrard said via Twitter the two leaders would speak about the bilateral relationship and supplying doses of the vaccine.

The vaccine has not been approved for use in Mexico, but the government is desperate to fill supply gaps for the Pfizer vaccine.

Besides Lopez Obrador, other Latin American leaders who have tested positive for the coronavirus are Brazil's President Jair Bolsonaro, Guatemala's Alejandro Giammattei, Honduras' Juan Orlando Hernandez and Bolivia's then-interim President Jeanine Anez. All have recovered.