The US surpassed the figure of 500,000 Covid-related deaths, the highest number of any country.
Globally, Brazil follows with a death toll of 247,000; Mexico is 180,000, India and United Kingdom stand at 156,000 and 121,000 respectively.
So far, the 28.1 million confirmed US infections is nearly double that of second-highest India (11 million) and Brazil (10.1 million), according to Johns Hopkins University research.
But the US ranks ninth in terms of deaths per 100,000 population, behind countries like the UK and Italy.
At least 90,000 more Americans are expected to have died with the virus by 1 June, an Institute for Health Metrics and Evaluation (IHME) projection says. By late May, the virus will kill around 500 Americans per day – down from approximately 2,000 now.
President Joe Biden addressing the nation said “As a nation, we can’t accept such a cruel fate. We have to resist becoming numb to the sorrow,” he said on Monday.
The president and vice-president, and their spouses, then observed a moment of silence outside the White House during a candle-lighting ceremony.
“Today I ask all Americans to remember. Remember those we lost and remember those we left behind,” President Biden said, calling for Americans to fight Covid together.
BBC NEWS reports that the president ordered all flags on federal property to be lowered to half mast for the next five days.
At the White House, he opened his speech by noting that the number of American deaths from Covid was higher than the death toll from World War One, World War Two, and the Vietnam War combined.
“Today we mark a truly grim, heartbreaking milestone – 500,071 dead,” he said.
“We often hear people described as ordinary Americans,” he went on to say. “There’s no such thing, there’s nothing ordinary about them.
”The people we lost were extraordinary. They span generations. Born in America, emigrated to America. So, many of them took their final breath alone in America.”
He drew on his own experience with grief – his wife and daughter were killed in a car crash in 1972 and one of his sons died from brain cancer in 2015.
“I know what it’s like to not be there when it happens. I know what it’s like when you are there holding their hands; there’s a look in their eye and they slip away,” he said.
“For me, the way through sorrow and grief is to find purpose.”
Mr Biden’s approach to the pandemic is different to his predecessor, Donald Trump, who cast doubt on the impact of the deadly virus and was viewed as having politicised the wearing of masks and other measures needed to prevent the spread of the virus.
On January 19, one day before Mr Biden took office, he held an event to mark 400,000 Americans dying of the disease. (BBC NEWS)