A former chief prosecutor at the International Criminal Court (ICC) has told the BBC that US air strikes on alleged drug smuggling boats would be treated under international law as crimes against humanity.

The comments by Luis Moreno Ocampo come as the Trump administration faces mounting questions over the legality of the attacks in the Caribbean Sea and Eastern Pacific— which have killed at least 66 people in the last two months.

The administration says it is in a formal armed conflict with South American traffickers who are bringing drugs into the US.

But Mr. Moreno Ocampo said the military campaign fell into the category of a planned, systematic attack against civilians during peacetime.

This, he said, meant that the campaign fell into the category of crimes against humanity.

These are criminals, not soldiers. Criminals are civilians, said Mr. Moreno Ocampo of the US allegations against the boat crews. They are criminals, and we should do better at investigating them, prosecuting them and controlling them, but not killing people, he told the BBC.

The White House said in response that President Donald Trump acted in line with the laws of armed conflict to protect the US from cartels trying to bring poison to our shores... destroying American lives. It highlighted that the ICC had no jurisdiction over the United States and argued that it was a biased, unserious entity.

It's ridiculous that they are now lecturing President Trump and running cover for evil narcoterrorists trying to murder Americans, said White House Deputy Press Secretary Anna Kelly.

Mr. Moreno Ocampo, a lawyer from Argentina who helped lead the 1985 prosecution of that country's former military junta, described the strikes as a very dangerous expansion of the president's remit to use lethal force. In the past, he said, alleged drug boats would be stopped, and suspects incarcerated.

The US is alleging it can kill whoever they want, and that's a huge change because in the past the US, in particular after 1945, was the guarantor of global peace to protect Western values, basically, he said. That's… a very bad trend for the world, added Mr. Moreno Ocampo.

The US is not a signatory to the Rome Statute that established the ICC and has recently sanctioned several of its judges in retaliation for the court's investigations related to the US and Israel.

Mr. Moreno Ocampo said: For me, it's very clear. A crime against humanity is a systematic attack against a civilian population, and there is no clarity why these people are not civilians, even [though] they could be criminals... and it's clearly systematic, because President Trump says they have planned and they organised this, so that should be the charge.