The number of Americans who have died from Covid-19 has surpassed 600,000 - the most of any nation - according to data from John Hopkins University.
The US also ranks highest in total number of recorded cases, with nearly 33.5 million infections since 2020.
This latest milestone comes as President Joe Biden's goal of getting 70% of US adults vaccinated by 4 July appears increasingly likely to fail.
Over 173 million people, around 52% of the US, have had at least one dose.
Roughly 43% of the US population, or about 144 million Americans, are fully vaccinated, according to the Centers for Disease Control and Prevention (CDC). The CDC says people are fully vaccinated at least two weeks after their final vaccine dose.
As of Tuesday, 600,012 people in the US have died of complications brought on by the coronavirus.
Brazil and India have reported the next highest death tolls, with Brazil at more than 488,000 deaths and India at more than 377,000.
It took around four months for the US to go from 500,000 to 600,000 deaths - about as long as it took to go from none to 100,000. It marks a significant change from the height of the pandemic when the death toll jumped from 300,000 to 400,000 in one month last winter.
But the country's vaccination rate has begun to fall to around one million doses administered per day - down from a high this April of nearly 3.4 million after it was first made available to all adults over 18.