US President Donald Trump said he was planning to impose a 50% tax on goods made in Brazil, escalating his fight with the South American country.

He announced the plan in his latest tariff letter, which was shared on social media.

In it, Trump accuses Brazil of "attacks" on US tech companies and of conducting a "witch hunt" against former far-right president Jair Bolsonaro, who is facing prosecution over his alleged role in a plot to overturn the 2022 election.

Responding in a social media post, Brazilian President Luiz Inácio Lula da Silva said an increase in tariffs on Brazil would be reciprocated, and he warned against any interference in the nation's judicial system.

Trump also sparred with Lula about Bolsonaro's trial earlier this week.

At the time, Lula said Brazil would not accept "interference" from anyone and added: "No one is above the law."

Also on Wednesday, Trump said a 50% tariff on copper imports, that he announced earlier this week, will come into effect on 1 August.

He said in a social media post that the decision was made due to national security concerns.

Trump has posted 22 letters to countries around the world this week, including trade partners such as Japan, South Korea and Sri Lanka, outlining new tariffs on their goods which he says will come into force on 1 August.

Those moves have largely served to revive plans he had put forward in April, but that were put on hold after financial markets recoiled at the measures.

But the message to Brazil was a far more targeted missive and threatened a significant increase from the 10% tariff the White House had previously announced on goods from the country.

Unlike many other countries, the US enjoyed a trade surplus with Brazil last year, selling more goods in the country than it purchased from it.

In the letter, Trump called the 50% rate "necessary... to rectify the grave injustices of the current regime".

He said he would order the US Trade Representative to launch a so-called 301 investigation into Brazil's digital trade practices.

Such a move would mark a turn towards a more established legal process that the US has used to impose tariffs in the past, toughening the threat. In his first term, Trump took a similar step over Brazil's consideration of a tax targeting tech firms.

Trump, in the letter, accused the Brazilian government of "insidious attacks on Free Elections, and the fundamental Free Speech Rights of Americans" including the censorship of "US Social Media platforms".

The US president's company Trump Media, which operates his Truth Social platform, is among the US tech companies fighting Brazilian court rulings over orders suspending social media accounts.

The country had also temporarily banned Elon Musk's X, formerly known as Twitter, after the platform refused to ban accounts that were deemed by Brazil to be spreading misinformation about the 2022 Brazilian presidential election.

Last month, Brazil's Supreme Court ruled that social media companies can be held responsible for content posted on their platforms.

In his letter, Trump also spoke favourably of former Brazilian president Bolsonaro, saying he "respected him greatly". He added that the ongoing trial against him is "an international disgrace".

Trump and Bolsonaro enjoyed a friendly relationship when their presidencies overlapped, with the pair meeting in 2019 at the White House during Trump's first term. Bolsonaro is often dubbed "Trump of the Tropics".

Both men subsequently lost presidential elections and both refused to publicly acknowledge defeat.

Bolsonaro, who governed Brazil between 2019 and 2022, is standing trial for allegedly attempting a coup with thousands of his supporters storming government buildings in the capital in January 2023 after Lula was victorious in the election.

Bolsonaro was in the United States at the time and has denied any links to the rioters or any involvement in the plot.

Earlier this week, Trump had compared Bolsonaro's prosecution to the legal cases he has similarly faced.

"This is nothing more, or less, than an attack on a Political Opponent - Something I know much about!" Trump had said. In response, Bolsonaro thanked the US president for his support.

Trump was also critical of the Brics summit in Rio de Janeiro, where the group of developing nations met on Sunday. Trump called the group, which includes Brazil, "anti-American" and said those countries would be charged an additional 10% tariff.

President Lula fired back on Monday against Trump's social media threats.

"He needs to know that the world has changed," Lula said. "We don't want an emperor."