Colombian President Gustavo Petro has said that a boat recently bombed by the US was "Colombian with Colombian citizens inside", an allegation the White House called "baseless".

The US has struck at least four vessels in the Caribbean in recent weeks, killing 21 people. The US government has said the strikes in international waters were targeting "narco-traffickers".

But it has not provided evidence or details about who or what is aboard, and the strikes have attracted condemnation in countries in the region amid concerns they breach international law.

The US Senate rejected a measure on Wednesday that would have barred President Donald Trump from using military force against the boats.

Petro replied to a post on X by US Senator Adam Schiff, a Democrat, who said he would vote to block strikes against vessels in the Caribbean as some lawmakers sought to challenge the use of the armed forces in Congress.

The Colombian president said that a "new war scenario has opened up: the Caribbean".

Petro added that "indications show that the last boat bombed was Colombian with Colombian citizens inside it.

"I hope their families come forward and report it. There is no war against smuggling; there is a war for oil and it must be stopped by the world. The aggression is against all of Latin America and the Caribbean."

Petro did not provide further details about the alleged identities of those on board. The US has not commented on the identities of the individuals killed in the strikes.

The White House said in a statement that it "looks forward to President Petro publicly retracting his baseless and reprehensible statement".

It said that while the two nations had "policy differences", the US remained "committed to close co-operation on a range of shared priorities, including regional security and stability".

The US says its strikes, which began on 2 September, had targeted vessels off the coast of Venezuela that it alleges were carrying illegal drugs.

The measure considered by the Senate on Wednesday, which would have required Trump to seek congressional approval for the strikes, was rejected in a 48-51 vote.

It had been introduced by Democratic Senators Schiff and Tim Kaine. The vote broke down mostly along partisan lines.

Earlier this month, a leaked memo sent to Congress said that the US was now categorising itself as being in a "non-international armed conflict".

Framing this as an active armed conflict is likely a way for the administration to justify the use of wartime powers, including killing "enemy fighters", even if they pose no violent threat.

Trump has already designated many cartels, including in Mexico, Ecuador and Venezuela, as terrorist organisations – granting US authorities more powers in their response to them.