Acceptable in headlines and on first reference in copy when referring to an officially sanctioned group of US-based athletes in an international competition such as the Olympics, World Cup, World Baseball Classic, etc.

In most cases, however, US (no periods) is preferable: Japan topped the US in the 2023 World Baseball Classic; Simone Biles qualified for the US team in the upcoming Olympics.

This is the only instance in which “USA” is ever used. Never “the Americans” or “the American team” or “Team America,” etc., unless appearing as part of a direct quote.