US President Donald Trump has announced a 50 percent tariff on Brazilian imports as he accused the country's leftist leadership of orchestrating a "witch hunt" against his right-wing ally, former leader Jair Bolsonaro.

Trump said countries seeking to challenge the dollar “are gonna have to pay a big price,” adding he doesn't think any of them is willing to pay that price.

Donald Trump's second presidency is already more disruptive than his first, Australia's foreign minister said on Wednesday, although she held hopes the country might still get an exemption when it comes to tariffs.