Family members of two men killed in a US missile strike against a suspected drug boat that was travelling from Venezuela filed a wrongful death lawsuit on Tuesday, alleging the pair were murdered in a “manifestly unlawful” military campaign targeting civilian vessels.

Civil rights lawyers filed the lawsuit in Boston’s federal court, marking the first court challenge to one of the 36 US missile strikes on vessels in the Caribbean Sea and Pacific Ocean authorised by President Donald Trump’s administration that have killed at least 126 people since September.

Family members of Chad Joseph and Rishi Samaroo — two Trinidadian men who were among six killed during an October 14 strike — in the lawsuit say the two men did fishing and farm work in Venezuela and had been returning to their homes in Las Cuevas, Trinidad, when they were attacked.

“These are totally unjustifiable killings by an administration that has claimed the right to abuse executive power with impunity,” said Brett Max Kaufman, a lawyer for the plaintiffs at the American Civil Liberties Union.

“And this lawsuit is a demand for accountability and a defence of the rule of law.”

His group and the Centre for Constitutional Rights filed the novel lawsuit under the Death on the High Seas Act, a maritime law that allows family members to sue for wrongful deaths occurring on the high seas, and the Alien Tort Statute, a 1789 law that allows foreign citizens to sue in US courts for violations of international law.

The lawsuit was filed by Lenore Burnley, Joseph’s mother, and Sallycar Korasingh, Samaroo’s sister, and seeks only damages from the US government for the two deaths, not an injunction that would prevent further strikes.

But the case could provide an avenue for a court to assess whether the October 14 strike was legal.

White House spokesperson Anna Kelly, in a statement, defended the strike, saying it was “conducted against designated narcoterrorists bringing deadly poison to our shores.”

“President Trump used his lawful authority to take decisive action against the scourge of illicit narcotics that has resulted in the needless deaths of innocent Americans,” Kelly said.

As of Tuesday, the death toll from those strikes was up to 126, including 10 who were believed to be dead after searches were suspended, according to a US defence official.

The Trump administration has framed the attacks carried out under US Defence Secretary Pete Hegseth’s direction as a war with drug cartels, alleging they were armed groups.

It has said its attacks comply with international rules known as the law of war or the law of armed conflict.

But the attacks have drawn scrutiny from Democrats and some Republicans in Congress, which has not authorised attacks on the drug cartels, and condemnation from human rights groups.

Legal experts have previously said the drug cartels do not fit the accepted international definition of an armed group.

Tuesday’s lawsuit argues that the killing of Joseph, 26, and Samaroo, 41, outside of an armed conflict and when they were not taking part in military hostilities against the US amounted to murder and should be deemed a wrongful death on the high seas and an extrajudicial killing under international law.

“If the US government believed Rishi had done anything wrong, it should have arrested, charged, and detained him, not murdered him,” Korasingh said in a statement. “They must be held accountable.”