"A translation of ISIS’s Al-Naba newsletter provided by the Counter Extremism Project shows ISIS wrote a wide-ranging piece on the attack. The piece said Jabbar had been influenced by its discourse and propaganda, noting the costs of the attack were negligible.

...

"ISIS's al-Naba statement confirmed that the terrorist group's propaganda helped inspire the New Year's Eve attacker and noted the significance of his claim of allegiance to the organization,” said Joshua Fisher-Birch, researcher at the Counter Extremism Project.

Fisher-Birch added that ISIS emphasized its propaganda network and encouraged other attacks on public events, part of a pattern of content encouraging lone-actor attacks."