US military officials have said American forces launched assaults on three alleged drug-smuggling boats, killing 11 in one of the deadliest days of the Trump administration’s months-long campaign against alleged traffickers.

The military action on Monday brought the number of fatalities caused by US strikes to 145 since September, when Donald Trump called on American armed forces to attack people deemed “narco-terrorists” on small vessels. There have been 42 known strikes in notorious drug-trafficking routes such as the Caribbean Sea and eastern Pacific Ocean, according to the Associated Press reported.

US Southern Command posted video to social media, showing this week’s strikes. Authorities insisted the boats transported drug-trafficking criminals but the video does not appear to provide information confirming this claim.

“Intelligence confirmed the vessels were transiting along known narco-trafficking routes and were engaged in narco-trafficking operations,” US Southern Command said. Officials added that four men were killed on one boat in the eastern Pacific, four on another vessel in the eastern Pacific, and three on a vessel in the Caribbean.

“No US military forces were harmed,” US Southern Command said.

The US Southern Command carried out two deadly boat strikes last week, similarly claiming those killed were suspected of drug trafficking.

Many have questioned the legality of the US boat strike initiative. Some legal experts have said the attacks are tantamount to extrajudicial military killings without an imminent threat of violence.

“Those being killed by US military strikes at sea are denied any due process whatsoever,” a recent analysis by the Washington Office on Latin America, an advocacy organization, said. Trump’s administration, the office said, was “asserting and exercising an apparently unlimited license to kill people that the president deems to be terrorists”.

The recent spate of strikes come weeks after US forces attacked Caracas, capturing the Venezuelan president, Nicolás Maduro, to face trial in New York on drugs, weapons and narco-terrorism charges.

While the Trump administration has portrayed boat strikes and Maduro’s capture as part of a fight against narco-terrorism, there has not been abundant evidence of trafficking rings.

The Pentagon had deployed more than a dozen warships to waters near Venezuela, to block drug trafficking and the illegal oil trade, the Washington Post reported. Several of those ships have since been dispatched eastward amid Trump’s military threats to Iran over its nuclear weapons program.