The U.S. military said it killed two people in a strike on an alleged drug-trafficking boat in the eastern Pacific Ocean on Monday, bringing the death toll to at least 170 since strikes began last September. 

U.S. Southern Command, which is responsible for Washington's forces in the region, said in a post on X that "the vessel was transiting along known narco-trafficking routes in the Eastern Pacific and was engaged in narco-trafficking operations."

"Two male narco-terrorists were killed during this action. No U.S. military forces were harmed," the post said.

CBS News reached out to U.S. Southern Command for evidence of narco-terror operations by the vessel. 

A spokesperson replied that they rely on "a rigorous process of intelligence gathering and analysis, which may include multi-source intelligence, surveillance, and reconnaissance to confirm illicit activity" prior to any operation.

"In this instance, the vessel in question was identified through coordinated intelligence efforts as operating along established narco-trafficking routes and was assessed to be engaged in activities consistent with narco-trafficking operations," the spokesperson said, adding, "For operational security reasons, we cannot discuss specific sources or methods."

The latest strike comes two days after U.S. military strikes killed five people in two boats, also in the eastern Pacific. One person survived those strikes, U.S. Southern Command said.

In at least six instances, people have survived the strikes on alleged drug trafficking boats, spurring efforts to find and rescue them in most cases. Authorities have called off several of those searches, though in one October operation, two survivors were picked up by a Navy helicopter and repatriated to their home countries of Ecuador and Colombia.

The military's handling of survivors has drawn intense scrutiny. During the first boat strike on Sept. 2, two people survived an initial strike but were killed in a follow-on attack, prompting accusations the second strike may have constituted a war crime. Democratic lawmakers who watched a video of the Sept. 2 operation were highly critical of the strike. The Defense Department and several congressional Republicans have insisted the survivors may have still been in the fight, warranting the follow-on strike.

The Trump administration has been targeting alleged "narco-terrorists" operating in Latin America, labeling the alleged drug smugglers as "unlawful combatants," and telling Congress the U.S. is embroiled in a "non-international armed conflict" with cartels.

But it has provided no definitive evidence that the vessels it targets are involved in drug trafficking, prompting heated debate about the legality of the operations.

International law experts and rights groups say the strikes likely amount to extrajudicial killings as they have apparently targeted civilians who do not pose an immediate threat to the United States.