Brazilian President Luiz Inácio Lula da Silva said on Thursday that he will impose retaliatory tariffs on the United States if President Donald Trump follows through on a pledge to boost import taxes by 50% over the South American country’s criminal trial against his predecessor, Jair Bolsonaro.

The US President has announced the imposition of a tariff on all Brazilian imports, triggering a diplomatic row with President Luiz Inácio Lula da Silva.

The timing of the announcement, which comes as former Brazilian president Jair Bolsonaro faces trial for allegedly plotting a coup, has intensified speculation that Trump is defending a political ally rather than responding to economic factors.