Terrorist group ISIS said it had killed the two men, identified as Norwegian citizen Ole Johan Grimsgaard-Ofstad and Chinese national Fan Jinghui, in its English-language online magazine Dabiq.

“We have no grounds to doubt the contents of the photos that have been published,” Norway’s Foreign Minister Boerge Brende told Reuters.

The U.N. Security Council added their voice to the outrage on Friday, and called on all countries to cooperate with China and Norway to help bring those responsible for the killings to justice, CNN said.

China’s president Xi Jinping vowed to bring ISIS to justice.