COLOMBIAN President Gustavo Petro said on Sunday that he will sue his Ecuadorian counterpart, Daniel Noboa, who has accused him of having ties to the leader of a ruthless criminal organisation.

Mr Petro announced his decision in a social media post, though he did not provide details of the lawsuit, including the country and venue in which he plans to file it.

His threat is the latest twist in the dispute between the presidents whose countries are locked in a trade dispute and experiencing the sharp end of the United States’ war on drugs.

Mr Noboa claimed in a story published by a Colombian newspaper on Saturday that Mr Petro had met members of Ecuador’s largest political opposition party, some of whom “have ties to Fito” — the alias of Adolfo Macias, leader of one of Ecuador’s most powerful cartels. 

Mr Macias was extradited to the US last year on drug- and weapon-trafficking charges.

Mr Noboa did not present any evidence to support his claim, and Mr Petro has denied knowing Mr Macias.

“I have decided to file a criminal lawsuit against President Noboa for his slander,” Mr Petro wrote on X on Sunday.

Mr Petro’s announcement comes during a dispute between the two leaders that has plunged Colombia and Ecuador into a trade war since January, when Mr Noboa unilaterally imposed tariffs on Colombian imports, citing a lack of control at their shared border.

Colombia responded with its own tariffs and a suspension of energy sales, while Ecuador progressively increased its tariff from 30 per cent to 50 per cent, and finally to 100 per cent.

The last increase will take effect next month.