March 25 (UPI) — U.S. Southern Command said it killed four men in a strike on an alleged drug trafficking boat in the Caribbean on Wednesday, the latest attack by the Trump administration in its aggressive crackdown on narcotics trafficking.

The Trump administration has killed at least 163 people and destroyed at least 47 vessels it accuses of trafficking drugs in international waters since Sept. 2, according to a Pentagon posture statement and subsequent SOUTHCOM releases. Wednesday’s strike was the third publicly reported since the U.S. military began its war with Iran.

The strikes have drawn criticism from Democrats and human rights organizations, which argue the Trump administration is violating international law by using the military for what critics say is essentially a law enforcement mission and by killing suspects who have not been charged with or convicted of any crime.

President Donald Trump argues that the United States is in “armed conflict” with drug cartels, at least 10 of which he has designated as terrorist organizations.

As it has with previous strikes, SOUTHCOM said in a statement that the vessel attacked Wednesday was operated by a designated terrorist organization and that intelligence confirmed it was transiting “along known narco-trafficking routes in the Caribbean and was engaged in narco-trafficking operations.”

No proof was provided.

A 15-second black-and-white aerial video accompanying the SOUTHCOM statement shows a boat being struck by an explosive. Flames and smoke are then seen trailing the vessel.

The Trump administration has been consistently attacking the alleged drug-trafficking vessels since early September, with a lull that followed the U.S. military’s January capture of Venezuela’s authoritarian leader, Nicolas Maduro.

Since the United States entered the war with Iran on Feb. 28, it has conducted two other strikes on alleged drug-trafficking boats — one on March 8, when six people were killed, and another on March 19, killing two people and injuring a third.