(BSS/AFP) - United Nations rights experts said Tuesday that the United States` covert actions and threats of using armed force against Caracas "violate Venezuela`s sovereignty and the UN Charter".

US President Donald Trump has waged a military campaign that he says is aimed at choking the flow of drugs from Latin America to the United States.

"These actions also violate the fundamental international obligations not to intervene in the domestic affairs or threaten to use armed force against another country," the three independent rights experts said.

"These moves are an extremely dangerous escalation with grave implications for peace and security in the Caribbean region."

At least six vessels, most of them speedboats, have been targeted by US strikes in the Caribbean since September, but Washington has provided no evidence that the people killed -- at least 27 so far -- were drug smugglers.

"Even if such allegations were substantiated, the use of lethal force in international waters without proper legal basis violates the international law of the sea and amounts to extrajudicial executions," said the experts, who were mandated by the UN Human Rights Council but do not speak on behalf of the United Nations.

At the same time, they said, groups like Tren de Aragua, which Trump has labelled a "terrorist" organisation, are not attacking the United States, meaning that Washington cannot invoke the "right to self-defence" under international law.

"Preparations for covert or direct military action against another sovereign State constitute an even graver breach of the UN Charter," said the experts, including the special rapporteurs on extrajudicial executions and on protecting human rights while countering terrorism.

Trump has indicated that he authorised covert CIA operations against Venezuela, without offering specifics.

Venezuelan President Nicolas Maduro says Washington is plotting to oust him, and Venezuela`s foreign minister welcomed the findings.

"The experts corroborate what we have denounced: the United States is manufacturing enemies to justify a supposed right to defence, which leads to massacres in the Caribbean Sea," Foreign Affairs Minister Yvan Gil said on Telegram.