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.

Adm Bradley did the right thing, said Democratic congressman Jim Himes, the ranking member of the House Intelligence Committee, after he heard from the admiral and viewed the video.

But what I saw in that room was one of the most troubling things I've seen in my time in public service, Himes said.

Democratic Representative Adam Smith, the highest-ranking Democrat on the House Armed Services Committee, released a joint statement with Himes calling for the video to be released publicly.

Concerns about the legality of military operations in the ongoing campaign against drug trafficking have been echoed by both parties, with many lawmakers advocating for further investigation into the matter.

The 2 September incident was the first of many US attacks that have led to more than 80 deaths in the Caribbean and Eastern Pacific. While the US insists the strikes are lawful, ongoing debates continue concerning the use of force against suspected criminals and the implications of targeting individuals who are regarded as no longer a threat.