File Photo: Mexican President Andres Manuel Lopez Obrador speaks during a press conference in Mexico City, Mexico, July 1, 2020. Photo: Xinhua

Mexican President Andres Manuel Lopez Obrador announced Sunday that he was infected with coronavirus, but said his symptoms were mild.

"I regret to inform you that I am infected with COVID-19. The symptoms are mild but I am already undergoing medical treatment," the 67-year-old said in a message on social media.

"As always, I am optimistic. We will come through this together," he said.

The left-wing populist is rarely seen wearing a mask in public, including at his daily news conferences, and has kept up most of his activities during the pandemic.

Lopez Obrador has continued his travels to different parts of the country and on Friday visited the northern state of San Luis Potosi.

He was criticized for being slow to impose a lockdown at the start of the pandemic and for continuing to hold rallies and greet supporters with handshakes and hugs.

Lopez Obrador suffered a heart attack in 2013 and underwent angioplasty. He also suffers from hypertension - a risk factor for COVID-19.

He joins other world leaders, including former US president Donald Trump, Brazilian president Jair Bolsonaro and British prime minister Boris Johnson, who have caught the virus.

Canadian Prime Minister Justin Trudeau tweeted that he wished his Mexican counterpart a "full and speedy recovery."

Former Mexican presidents Felipe Calderon (2006-12) and Enrique Pena Nieto (2012-18) also took to Twitter to wish Lopez Obrador a successful recovery.

AFP