President Donald Trump’s pardon last week of four former Blackwater Worldwide military contractors convicted of killing 14 Iraqis in 2007 violates US obligations under international law, experts with the United Nations said om Wednesday in urging member-states to condemn the presidential action.

“Pardoning the Blackwater contractors is an affront to justice and to the victims of the Nisour Square massacre and their families,” said Jelena Aparac, the chair-rapporteur of the U.N. Working Group on the use of mercenaries that issued the statement.

Nicholas Slatten was convicted of first-degree murder and Paul Slough, Evan Liberty and Dustin Heard were convicted of voluntary and attempted manslaughter by US courts in 2015 for their involvement in the 2007 shooting in Nisour Square that left 14 civilians dead and 17 wounded. Slatten was sentenced to life while the other three received at least 12-year-imprisonment orders.

The five independent UN experts on Wednesday said on top of violating US obligations under international law, the pardons undermine humanitarian law and international human rights.

“Ensuring accountability for such crimes is fundamental to humanity and to the community of nations,” Aparac said. “Pardons, amnesties or any other forms of exculpation for war crimes open doors to future abuses when states contract private military and security companies for inherent state functions.”

The working group said it is “extremely concerned” that by permitting contractors to operate with impunity other nations will seek to circumvent international humanitarian law.

Despite Trump saying the pardons were “broadly supported by the public,” those abroad, including family members of the victims, and those at home condemned them.

Sen. Ben Sasse, R-Neb., said, “this is rotten to the core.”

Retired Gen. David Petraeus, former head of US Central Command, and Ryan Crocker, former ambassador to Iraq, said in a joint statement that the pardons tell the world “Americans abroad can commit the most heinous of crimes with impunity.”

“It places our military and civilian personnel at increased risk and it betrays our most fundamental values,” the pair said. “American prestige, credibility and security have all been seriously undermined.” CURRENTPH