The United Nations’ human rights office said on Wednesday that it’s “deeply concerned” by U.S. President Donald Trump’s pardons of four former government contractors convicted in a 2007 massacre in Baghdad that left more a dozen Iraqi civilians dead.

The four men’s pardons were among 15 that were announced on Tuesday.

Supporters of the former contractors at Blackwater Worldwide had lobbied for pardons, arguing that the men had been excessively punished in an investigation and prosecution they said was tainted by problems and in which exculpatory evidence was withheld.

“These four individuals were given sentences ranging from 12 years to life imprisonment, including on charges of first-degree murder,” U.N. human rights office spokeswoman Marta Hurtado said in a statement released in Geneva. “Pardoning them contributes to impunity and has the effect of emboldening others to commit such crimes in the future.”

She said that “victims of gross human rights violations and serious violations of international humanitarian law also have the right to a remedy,” which includes a right to “see perpetrators serve punishments proportionate to the seriousness of their conduct.”

The case caused an international uproar over the use of private security guards in a war zone.

It followed a complicated legal path since the killings at Baghdad’s Nisoor Square in September 2007, when the men — former veterans working as contractors for the State Department — opened fire at the crowded traffic circle.

Prosecutors asserted the heavily armed Blackwater convoy launched an unprovoked attack using sniper fire, machine guns and grenade launchers. Defense lawyers argued their clients returned fire after being ambushed by Iraqi insurgents.

(AP)