The Pentagon earlier this week carried out its 20th strike on a boat it claimed was trafficking drugs, killing all four on board, officials claimed.

The U.S. killed the "narco-terrorists" in the Caribbean Sea, a Pentagon official, speaking on condition of anonymity, told The Hill on Thursday.

There were no survivors following the attack, part of what the Trump administration argues is a military campaign, which kicked off in early September, to curb the flow of illegal drugs into the U.S.

The military has killed at least 80 people so far in the operations, which have prompted pushback from both sides of the aisle and have been deemed illegal by national security lawyers. The strikes have taken place in both the Caribbean and the Eastern Pacific.

The Pentagon has not shared more information about the latest strike, including where those killed originated from, and whether the vessel was affiliated with a designated terrorist organization. The latest attack was reported earlier by CBS News.

The Monday attack comes as the administration has amassed a massive military presence in the U.S. Southern Command (Southcom) region, deploying warships, F-35 fighter jets, spy planes and other military assets in the area.

The Navy on Tuesday confirmed the world`s largest aircraft carrier, the USS Gerald R. Ford, and its strike group arrived in the Southcom region, which includes the Caribbean and Central and South America. The carrier, which has more than 4,000 sailors, carries F/A-18 Super Hornets fighter jets and long-range Tomahawk missiles.

Amid the strikes, Trump and other officials have turned up the pressure against Venezuelan President Nicolás Maduro, calling him an "illegitimate leader." The president signaling during a recent CBS "60 Minutes" interview that Maduro`s days are numbered.

The strikes have prompted pushback from Democrats, who have argued that the strikes are illegal and that the president needs authorization from Congress to continue the counter-narcotics campaign.

U.S. allies including the United Kingdom have also overtly distanced themselves from the U.S. over the attacks, which they believe are illegal.