Defense Secretary Pete Hegseth announced Wednesday that the U.S. military carried out another strike on a boat he said was carrying drugs in the eastern Pacific Ocean, killing all four people aboard, as the Trump administration pursues its divisive campaign against drug cartels in the waters off South America.

Hegseth, who`s been traveling in Japan and Malaysia, said in a social media post that intelligence determined the craft was "transiting along a known narco-trafficking route, and carrying narcotics." He said the strike was conducted in international waters and no U.S. forces were harmed.

A video posted by Hegseth shows a boat exploding into flames and smoke. It was the 14th strike since the campaign began in early September, while the death toll has grown to at least 61.

The Trump administration also has been building up an unusually large force of warships in the region, carrying Marines and aircraft. Their presence has fueled speculation that the moves are aimed at ousting Venezuelan President Nicolás Maduro, whom the U.S. has accused of narcoterrorism.

President Donald Trump has justified the attacks on the boats as a necessary escalation to stem the flow of drugs into the United States. He has asserted the U.S. is engaged in an "armed conflict" with drug cartels, relying on the same legal authority used by the Bush administration when it declared a war on terrorism after the Sept. 11, 2001, attacks.

But as the number of strikes has grown, a debate in Congress has escalated over the limits of the president`s power. The attacks have occurred without any legal investigation or a traditional declaration of war from Congress, and some lawmakers have raised questions about the lack of hard evidence to justify the killings.

The Trump administration has shown no evidence to support its claims about the boats that have been attacked, their connection to drug cartels, or even the identity of the people killed in the strikes.

Sen. Mark Warner, the ranking Democrat on the Senate Intelligence Committee, said Wednesday that the Trump administration has briefed Republicans - but not Democrats - on the boat strikes.

The military briefing at the Capitol comes as the Senate is facing a potential vote on a war powers resolution that would prohibit strikes in or near Venezuela unless Congress approves the military action.

"Shutting Democrats out of a briefing on U.S. military strikes and withholding the legal justification for those strikes from half the Senate is indefensible and dangerous," Warner of Virginia said in a statement.

"Decisions about the use of American military force are not campaign strategy sessions, and they are not the private property of one political party," he said.

The briefing was conducted by officials from the Defense and Justice departments for the GOP leadership and senators, according to a person familiar with the situation and granted anonymity because they were not authorized to discuss it.

Warner demanded a similar briefing for the Democrats.