A US Navy admiral testified that Defence Secretary Pete Hegseth did not give the order to 'kill them all' during a controversial second US military strike on an alleged drug boat in the Caribbean, multiple lawmakers have said.

The affirmations by Democratic and Republican lawmakers were made after viewing footage of the 2 September double-strike incident and hearing from Adm Frank Bradley in closed-door hearings.

The briefing before members of the House of Representatives and later the Senate came as questions continued around the legality of military force used against suspected drug boats.

The White House has said Adm Bradley was responsible for the strikes and that he acted within the law.

On Thursday evening, the US military posted on X that it had killed four people in another boat strike in the eastern Pacific Ocean at Hegseth's direction.

Prior to news of the latest strike, lawmakers reacted to the testimony, with the most senior Democrat on the House intelligence committee, Jim Himes, saying Adm Bradley had his respect and should have the respect of all of us.

He added: But what I saw in that room was one of the most troubling things I've seen in my time in public service.

Representative Adam Smith and Himes called for the video from the first strike to be released publicly, stating that the briefing left them with more questions than answers.

Senator Tom Cotton, chair of the Senate Intelligence Committee, supported Adm Bradley, saying he did exactly what was expected of him during the operation.

The strikes have drawn bipartisan concerns regarding their legality under international law, particularly the implications of attacking individuals who survived the initial assault.

The incident marks a troubling chapter in US military engagement in the region, as lawmakers and advocacy groups continue to scrutinize the ramifications of such actions on civilians and sovereign nations.