The US has 1.5 million coronavirus cases and nearly 92,000 deaths, according to Johns Hopkins University.
In second place is Russia, with nearly 300,000 confirmed cases.
President Donald Trump has argued it is “a badge of honour” that the US has the world’s highest number of confirmed Covid-19 infections.
“I look at that as, in a certain respect, as being a good thing because it means our testing is much better,” he said at the White House.
Mr Trump was hosting his first cabinet meeting since the US outbreak began.
“By the way,” he told reporters, “you know when you say that we lead in cases, that’s because we have more testing than anybody else.”
“So when we have a lot of cases,” he continued, “I don’t look at that as a bad thing, I look at that as, in a certain respect, as being a good thing because it means our testing is much better.”