US 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 double-strike incident on 2 September and hearing from US Navy Adm Frank Bradley in closed-door hearings on Thursday.

The briefing before members of the House of Representatives and then 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 move, and that he acted within the law.

After the briefing, 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.

“The briefing left us with more questions than answers, and Congress must continue to investigate this matter and conduct oversight,” they said.

Republican Senator Tom Cotton, chair of the Senate Intelligence Committee, said Adm Bradley and Hegseth “did exactly what we would expect them to do”.

“I saw two survivors trying to flip a boat loaded with drugs bound to the United States back over so they could stay in the fight,” Cotton said.

Republican House Representative Rick Crawford also defended the strikes and said there was “no doubt in my mind” that they were done in a way that was professional.

Senator Jack Reed, a Democrat, said in a statement he was “disturbed” by what he saw, adding that his party would continue to investigate the incident.

The revelation there were two strikes when the first left survivors has raised new questions over the legality of the administration’s deadly ongoing campaign against boats, due to what the rules of conflict say about targeting wounded combatants.

US President Donald Trump has said he has “no problem” with video of the second strike being made public. Footage of the first strike has already been released.

During the incident, two survivors of the first strike tried to climb back onto the boat before the vessel was hit a second time, US media including CBS reported. A source said the pair appeared to be trying to salvage drugs.

Adm Bradley was also expected to tell the high-ranking US lawmakers on Thursday that the survivors were a legitimate target because their boat was still thought to contain drugs, according to a US official who spoke to the Reuters news agency.

The 2 September incident was the first in a series of ongoing US attacks against vessels that have left more than 80 people dead in both the Caribbean and Eastern Pacific.

While US officials have insisted the 2 September attack was lawful, a full picture is still emerging of what happened that day.

The Washington Post was the first last week to report that two people had survived the first strike, and that Hegseth had allegedly ordered a second attack to kill them.

At the time, Hegseth immediately condemned the reporting as “fabricated, inflammatory and derogatory”, while Pentagon spokesman Sean Parnell said the “entire narrative was false”.

The existence of a second strike was later confirmed by the White House. Press Secretary Karoline Leavitt said this week the order came not from Hegseth but from Adm Bradley, who acted “well within his authority and the law”.

On Tuesday, Hegseth said he had watched the initial strike as it took place before moving on to other meetings. He said he “did not personally see survivors”, which he attributed to the flaming wreckage and “the fog of war”.

Later that day, the defence secretary recalled, he was informed that Adm Bradley decided to “sink the boat and eliminate the threat”, a move he considered justified.

The issue has drawn concern from Democratic and Republican lawmakers alike, many of whom had already criticised the military campaign more generally.

As well as the lethal strikes on suspected drug-smuggling boats, the US has expanded its military presence in the Caribbean.

Venezuela itself has repeatedly condemned the strikes, and has accused the White House of stoking tensions in the region with the aim of toppling the government.

Trump has claimed that the strikes have led to a massive reduction in drug trafficking through maritime routes, without providing evidence.

Evidence that the targeted individuals in each case were drug traffickers has likewise not been publicly provided.

Multiple experts who spoke to the BBC have raised serious doubts that the second strike on survivors on 2 September could be considered legal under international law.

A former chief prosecutor at the International Criminal Court (ICC) previously told the BBC that US air strikes on alleged drug smuggling boats would be treated under international law as crimes against humanity.

“These are criminals, not soldiers. Criminals are civilians,” he said.

The survivors may have been subject to protections provided to shipwrecked sailors, or to those given to troops who have been rendered unable to continue fighting.

The Trump administration has cast its operations in the Caribbean as a non-international armed conflict with the alleged drug traffickers.

The rules of engagement in such armed conflicts – as set out in the Geneva Conventions – forbid the targeting of wounded participants, saying that those participants should instead be apprehended and cared for.

Adm Bradley is yet to give any public comment on the matter.

One of the dozens of people who have been killed in the ongoing US strikes is believed to be Alejandro Carranza, a Colombian, who was last seen on 14 September.

Carranza’s family have now filed a complaint with the Inter-American Court of Human Rights (IACHR) in Washington, BBC Mundo has confirmed.