The strict "circuit-breaker" measures will come into force on Saturday and last until May 31. They include school and non-essential commerce closures and the banning of social, religious and sporting events in the nation of 45 million people.

"We are living the worst moment since the pandemic began," Fernandez said. "Today as never before we must all take care of ourselves to avoid all the losses that we can."

Citizens who are not classed as essential workers will be allowed to be out close to their homes between 6 a.m. and 6 p.m.; otherwise, they must stay at home.

The restrictions come as the government accelerates a vaccination campaign that has lagged ambitious initial plans. So far, only 4.7% of the population has been fully inoculated and 18.4% has received at least one dose, according to a Reuters analysis.

Fernandez also announced an economic rescue package for sectors worst-hit by the pandemic, which has exacerbated a crisis that has plagued the country for the past three years and left millions of Argentines in poverty.

Argentina posted 35,884 new COVID-19 cases on Thursday after hitting a record high 39,652 on Wednesday. Total infections number some 3.45 million, which puts the country ahead of hard-hit Brazil on a per capita basis and has pushed hospital intensive care units to near-saturation. There have been 72,699 confirmed deaths.