FILE PHOTO: U.S. President Donald Trump attends a meeting with Argentina's President Javier Milei (not pictured) during the 80th United Nations General Assembly, in New York City, New York, U.S., September 23, 2025. REUTERS/Al Drago/File Photo

By Phil Stewart and Idrees Ali

WASHINGTON (Reuters) -President Donald Trump has determined the United States is engaged in "a non-international armed conflict" with drug cartels, according to a document notifying Congress of its legal justification for deadly U.S. strikes on boats off Venezuela.

The text of the document, which was reviewed by Reuters on Thursday, was briefed to lawmakers by the Pentagon's top attorney this week as experts question the legality of killing suspected drug traffickers at sea instead of apprehending them and their cargo.

The U.S. military has blown up at least three suspected drug boats in the past month and killed at least 17 people, in what critics say is the latest effort by Trump to test the scope of his powers as U.S. president. The document describes those killed as "unlawful combatants."

The document did not appear to provide any new legal rationale other than what Trump and his allies have said publicly, arguments that some former military lawyers say fail to satisfy requirements under the law of war.

It was not clear if the determination was intended to provide a justification for future military strikes on cartels, or if it was mainly to explain past actions.

Trump said on Tuesday his administration is considering attacking drug cartels "coming by land" in Venezuela, actions that could raise further legal questions.

The document said Trump had determined that drug cartels were effectively non-state armed groups whose actions "constitute an armed attack against the United States."

"The President determined that the United States is in a non-international armed conflict with these designated terrorist organizations," according to the text of the document.

"The President directed the Department of War to conduct operations against them pursuant to the law of armed conflict," it said, using the Republican president's preferred name for the Defense Department.

The Pentagon did not immediately respond to a request for comment.

LEGAL AUTHORITY FOR STRIKES IN QUESTION

Legal experts have questioned why the U.S. military is carrying out the strikes instead of the Coast Guard, which is the main U.S. maritime law enforcement agency, and why other efforts to halt the shipments aren't made before resorting to deadly strikes.

"Applying a new label to an old problem does not transform the problem itself – nor does it grant the U.S. president or the U.S. military expanded legal authority to kill civilians," wrote Mark Nevitt, a former Navy lawyer who is now an associate professor at Emory University School of Law.

The Trump administration has argued so far that the strikes send a clear message to the drug cartels and noted that it designated them terrorist organizations earlier this year.

Addressing a gathering of senior generals and admirals this week in Quantico, Virginia, Trump defended the strikes by saying each boat has enough narcotics to kill 25,000 people. He also said the strategy was stemming the flow of seaborn drugs through the Caribbean.

"Now we have a problem. General Caine says, sir, there are no boats out there, not even fishing boats. They don't want to go fishing," Trump said, referring to General Dan Caine, the chairman of the Joint Chiefs of Staff.

"I don't blame them. There'll be no fishing today, you know. But it's amazing what strength will do," Trump said.

U.S. Senator Jack Reed of Rhode Island, the top Democrat on the Armed Services Committee, said the Trump administration has failed to provide Congress with any credible justification or intelligence to justify its actions.

"Every American should be alarmed that their president has decided he can wage secret wars against anyone he calls an enemy," Reed said in a statement.

(Reporting by Phil Stewart; Editing by Don Durfee and Bill Berkrot)