Ban Ki-moon has condemned the attack on Camp Liberty, the refugee camp for the People’s Mojahedin Organization, also known as the Mujahedin-e Khalq (MEK), and he called on Iraqi authorities to investigate the matter.

Reuters reports that the UN Secretary General urged the Iraqi government to investigate the attack and bring the perpetrators to justice.

U.S. spokesperson Victoria Nuland described the attack on Liberty Camp as a “terrorist attack” and called for a thorough investigation of the incident. The U.S. State Department reminded the Iraqi government that its commitments require it to provide security for Camp Liberty.

On Saturday, Camp Liberty became the target of rocket attacks that left at least six people dead and scores wounded. The leadership of the dissident Iranian group say their members are living in appalling conditions in this camp and need to be returned to Camp Ashraf, where they were settled before.

The MEK members had lived in Camp Ashraf and, under a deal brokered by U.S. authorities, they were moved to Camp Liberty until the United Nations could find them another country for resettlement.

Their return to Iran is out of the question since any link to the dissident group is enough to warrant a death penalty from the Iranian judiciary.

MEK had been on the list of U.S. terrorist groups and was removed in the course of negotiations for the resettlement from Camp Ashraf.