The United States has carried out strikes against three vessels in international waters in the Pacific Ocean, according to the US military.

The US Southern Command said, without providing evidence, that the targets were "narco-trafficking" vessels travelling as a convoy.

A US official, speaking on the condition of anonymity, said eight people abandoned their vessels during the attack on Tuesday.

The United States has been building up its forces in the Caribbean. (Reuters: Eva Marie Uzcategui)

The United States Coast Guard is searching for survivors.

The US has built up a massive military presence in the Caribbean amid escalating tensions between US President Donald Trump and Venezuelan President Nicolás Maduro.

Mr Trump's administration has carried out more than 30 strikes against suspected drug boats in the Caribbean and Pacific since September in a campaign that has killed at least 110 people.

The Coast Guard said it had deployed a C-130 aircraft to look for survivors and was working with vessels in the area.

"Three narco-terrorists aboard the first vessel were killed in the first engagement. The remaining narco-terrorists abandoned the other two vessels, jumping overboard and distancing themselves before follow-on engagements sank their respective vessels," Southern Command wrote on X.

Earlier survival stories

This is not the first time during the Trump administration there have been survivors of a US strike on boats. 

In October, two survivors were repatriated to their home countries after surviving a US military strike.

Later that month, Mexican authorities launched a search and rescue effort after another US strike left a survivor but that person was not found.

The decision to strike the vessels but not the survivors comes after it was revealed that during a September attack, the US military carried out a follow-up strike against a suspected drug vessel that had two survivors on it.

The lethal strikes on drug vessels are part of a broader campaign that the Trump administration says is aimed at cutting off the supply of illegal drugs. 

Legal experts and US Democratic politicians have questioned the legality of the strikes.

Mr Trump said on Monday that the US had "hit" an area in Venezuela where boats were loaded with drugs, marking the first known time Washington had carried out land operations in the country. 

Officials have said the land strike was not carried out by the US military and Mr Trump has previously said he had authorised the CIA to carry out covert operations in Venezuela.

The US issued new Venezuela-related sanctions on four crude oil tankers and four firms, according to a notice published on the US Treasury Department website on Wednesday.

Reuters