The US and Brazil each recorded more than 100,000 cases over the seven days from June 15 to June 21, the World Health Organisation (WHO) said, the only two countries with such high infection numbers.
The New York Times called it a "stinging blow to American prestige in the world and a repudiation of President (Donald) Trump's handling of the virus in the United States."
Trump claimed over the weekend that he ordered a slowdown of Covid-19 testing as the high figures were making the US "look bad".
"By having more cases, it sounds bad, but actually what it is, is we're finding people," he told reporters today. "Many of those people aren't sick or very little. You know, they may be young people.
"Here's what I say: Testing is a double-edged sword."
Dr Anthony Fauci, a leading member of the White House Coronavirus Task Force and top infectious diseases expert, warned in an interview with the Telegraph last week that travel between the UK and the US, which all but halted in mid-March, could remain off-limits for some time.
The ban could last until a vaccine is developed, although it may be before that. He said lifting it would be "more likely months than weeks."
Prohibiting American travellers from entering Europe would have significant economic, cultural and geopolitical ramifications. The move will likely be seen as a snub by the Trump Administration, which could decide to introduce reciprocal measures.
The Administration has already this week suspended new visas for specialist foreign workers in a bid to boost jobs for Americans.