US airstrikes on alleged drug-trafficking boats in the Caribbean Sea are an "act of tyranny", Colombia's President Gustavo Petro told the BBC in an interview where he also called for criminal proceedings against US officials if investigations find Colombians were killed in the attacks.

Donald Trump has cast the strikes, which have reportedly killed 17 since they began this month, as needed to stop the flow of fentanyl and other illegal narcotics into the US.

Legal experts and lawmakers, though, have questioned if they violate international human rights laws.

"Why launch a missile if you could simply stop the boat and arrest the crew?" said Petro. "That's what one would call murder."