U.S. Trade Representative Jamieson Greer said on Tuesday he had launched an investigation into Brazil's "unfair" trading practices, a week after President Donald Trump threatened a 50% tariff on imports from Latin America's largest economy.

Last week, the US president urged Brazilian authorities to end their prosecution of the country's former President Jair Bolsonaro.

The probe will determine if Brazil's economic policies and practices in a number of areas are "unreasonable or discriminatory and burden or restrict US commerce," the Office of the US Trade Representative said in a statement.