Scores of legal organizations and hundreds of lawyers from around the world have told US President Joe Biden that broad economic sanctions imposed by the United States amount to collective punishment and violate international law, and that it should end.

In a letter addressed to Biden, the signers called for the US to "comply with the international law by ending the use of broad, unilateral coercive measures that extensively harm civilian populations".

The letter said the unilateral application of certain economic sanctions by Washington constitutes collective punishment, "which is considered a war crime" and prohibited by the Geneva Conventions.

Collective punishment has become a standard practice of US foreign policy through sanctions, and the US imposes them more than any other country, the letter said.

While the use of sanctions is different from conventional warfare, "its collective impact on civilians can be just as indiscriminate, punitive, and deadly", the signatories said.

Hundreds of millions of people currently live under the sanctions, and notable cases include Cuba, Iran, Syria and Venezuela.

The sanctions "can spark and prolong economic crisis, hinder access to essential goods like food, fuel and medicine, and increase poverty, hunger, disease and even death rates, especially among the children", the letter said.

Civilian suffering is not merely an incidental cost of sanction policies, but it is also the intent, the letter said. It cited comments by Mike Pompeo, former US secretary of state, about the effectiveness of the Donald Trump administration's sanctions against Iran. He said: "Things are much worse for the Iranian people, and we're convinced that will lead the Iranian people to rise up and change the behavior of the regime."

US officials are aware that sanctions cause suffering.

Conditions induced by sanctions often drive mass migration, as in Cuba and Venezuela recently.

Human rights groups have said that more than 7 million people — about 25 percent of Venezuela's population — have fled the South American country in the past decade.

The letter echoes a recent report by Michael Fakhri, a United Nations special rapporteur, who spent two weeks in Venezuela to assess the situation.

Economic crisis

"I saw firsthand how unilateral coercive measures in the form of economic sanctions have constrained the government's fiscal ability to implement their social protection programs and deliver basic public services," Fakhri wrote in his report.

Nearly 82 percent of Venezuelans live in poverty based on income levels, and 53 percent are exposed to extreme poverty, with insufficient income to purchase a basic food basket.

Fakhri also recommended lifting sanctions on Venezuela.

"The United States does not consider itself to be at war with these states that it's imposing sanctions on, and nevertheless is doing things that have effects that states have outlawed even in the context of war," Ntina Tzouvala, associate professor at the Australian National University College of Law, told Bloomberg.

She said the US government's increased targeting of financial transactions and aggressive prosecutions by the Justice Department "creates a culture of overcompliance from private actors".

Agencies contributed to this story.