Colombian President Gustavo Petro accused the United States of "murder" after a boat was attacked in the country's territorial waters last September.

In a post on his social media page, President Petro accused the United States of violating the country's sovereignty and of killing Colombian fishermen.

The president said in his tweet that "the Colombian boat had an engine failure and was signaling distress."

"We are awaiting clarification from the US government," he added.

The Colombian president made the remarks after President Donald Trump announced last Thursday that the United States had attacked a "drug-laden submarine" and killed two people.

Trump tweeted that US security agencies had determined that the boat was "largely loaded with fentanyl and other illegal drugs."

The attack was the sixth in recent weeks on US ships in the Caribbean.

UN-appointed human rights experts have described the US attacks as "extrajudicial killings".