NPR interviews with current and former officials reveal more of the backstory around the military's strikes in the Caribbean.

The strike is at least the 21st since the Trump administration began using the tactic to deter drug trafficking in September.

The United States conducted another attack on an alleged drug trafficking boat in the eastern Pacific on Saturday, killing three people aboard, the Pentagon said on Sunday.

A Pentagon official says the U.S. military's 20th strike on a boat accused of transporting drugs has killed four people in the Caribbean Sea.

The U.S. war on drugs has always entailed a degree of pressure. The Trump administration's strikes on suspected drug-smuggling boats charts a new course of noncooperation.

President Claudia Sheinbaum said Thursday that her government had reached an agreement with its U.S. counterpart for the Mexican Navy to intercept vessels suspected of transporting drugs in international waters off Mexico's coast.

The lawyer at U.S. Southern Command, which oversees the operations against alleged drug-smuggling boats near Venezuela, disagreed that the strikes are legal and was overruled, according to six sources.

President Donald Trump has justified American military strikes on boats suspected of smuggling drugs by saying the longtime U.S. strategy of interdicting such vessels has been a major failure.