WASHINGTON (AP) — The U.S. military launched a strike on another boat accused of carrying drugs in the eastern Pacific Ocean on Tuesday, killing four people in the fourth such attack announced in the past few days.

The operation is the latest in a series of strikes on vessels that the Trump administration says were trafficking drugs in Latin American waters, a campaign that began more than seven months ago and continues even as the military has been preoccupied with the Iran war.

The latest strike brings the death toll to 175 since the operations began in early September. The U.S. Coast Guard has suspended the search for one survivor from an attack Saturday.

U.S. Southern Command posted aerial video on social media Tuesday showing a vessel bobbing in the water before being struck by a projectile and exploding. The military earlier said it struck two boats on Saturday and a third on Monday.

The military said all the vessels were “operated by Designated Terrorist Organizations” and that intelligence confirmed they “were transiting along known narco-trafficking routes in the Eastern Pacific and were engaged in narco-trafficking operations” but did not provide evidence.

President Donald Trump has said the U.S. is in “armed conflict” with cartels in Latin America and has justified the attacks as a necessary escalation to stem the flow of drugs into the United States and fatal overdoses claiming American lives. But his administration has offered little evidence to support its claims of killing “narcoterrorists.”

The strikes began months ahead of the U.S. raid in January that captured then-Venezuelan President Nicolás Maduro. He was brought to New York to face drug trafficking charges and has pleaded not guilty.

Critics have questioned the overall legality of the boat strikes as well as their effectiveness, in part because the fentanyl behind many fatal overdoses is typically trafficked to the U.S. over land from Mexico, where it is produced with chemicals imported from China and India.