Pentagon chief Pete Hegseth says attacks take place in international waters amid mounting criticism against US campaign.

The United States has carried out another set of military strikes against what it says are drug boats in international waters headed to the country.

Pentagon chief Pete Hegseth said on Monday that the US military targeted two vessels in the eastern Pacific Ocean on Sunday, killing six people.

“These vessels were known by our intelligence to be associated with illicit narcotics smuggling, were carrying narcotics, and were transiting along a known narco-trafficking transit route in the Eastern Pacific,” he wrote in a social media post.

“Both strikes were conducted in international waters, and three male narco-terrorists were aboard each vessel. All six were killed. No US forces were harmed.”

The administration of President Donald Trump has faced mounting criticism over such attacks, including accusations of violating domestic and international law.

But Washington appears to be stepping up the campaign. Sunday’s deadly double attack was the fourth this month. Previous strikes in the Pacific and Caribbean Sea killed at least eight people, according to US authorities.

The Trump administration started targeting boats in the Caribbean in September and later expanded its military push to the Pacific Ocean.

The US has carried out 18 strikes on vessels so far, killing dozens of people.

Last month, United Nations rights chief Volker Turk said the US attacks have no justification under international law.

“These attacks – and their mounting human cost – are unacceptable,” Turk said. “The US must halt such attacks and take all measures necessary to prevent the extrajudicial killing of people aboard these boats, whatever the criminal conduct alleged against them.”

The US has described the attacks as “counterterrorism” operations after having designated drug cartels as “terrorists”.

“Under President Trump, we are protecting the homeland and killing these cartel terrorists who wish to harm our country and its people,” Hegseth said on Monday.

Other than grainy footage showing the strikes, the Trump administration has not provided concrete proof that the vessels targeted were carrying drugs.

Trump himself has previously joked that fishermen are now afraid to operate in the Caribbean off the coast of Venezuela.

Critics have questioned why US authorities would not monitor the boats and intercept them when they enter the country’s territorial waters instead of extrajudicially executing the suspects.

The strikes have sparked regional tensions, particularly with Venezuela, with Trump accusing its president, Nicolas Maduro, of links to “narcoterrorists”.

The ramped-up US military campaign near Venezuela has raised speculation that Washington may be preparing for conflict in the oil-rich South American country.

This month, Trump suggested that war with Venezuela is unlikely but said Maduro’s days are numbered.