In what would mark the first attack by the terror group on U.S. soil, ISIS has claimed responsibility for the shooting that took place outside a Prophet Mohammed cartoon contest in Texas. The group also warned of more attacks to come.
In an address aired on its official radio channel Tuesday, the group said two of it soldiers opened fire outside the event in Garland, a suburb of Dallas.
The two gunmen, Elton Simpson and Nadir Soofi, only wounded a security guard before police shot and killed them.
The ISIS radio announcer referred to Simpson and Soofi as "brothers." The announcement concluded with the warning:
"We say to the defenders of the cross, the U.S., that future attacks are going to be harsher and worse. The Islamic State soldiers will inflict harm on you with the grace of God. The future is just around the corner."
While ISIS has claimed responsibility, it comes a full two days after the attack and there is currently no immediate indication that the terror group, which occupies Iraq and Syria, actually had contact with Simpson or Soofi, who both lived in Phoenix.
ISIS is known to be struggling, as coalition airstrikes reduce its potency and its vast territory creates legitimate governance issues for the poorly run group. Many cities occupied by ISIS are chronically short of food, medicine and energy.
The group also has challenges with internal discipline, with its members repeatedly raping women and children in territory they control.
While U.S. authorities are investigating the links to international terrorism, there are clues that one of the gunmen was an ISIS sympathizer.
Moments before the attack, Simpson posted the tweet: "May Allah accept us as mujahideen."
Another tweet said he and his fellow attacker had pledged allegiance to "Amirul Mu'mineen," which means "the leader of the faithful." This likely refers to ISIS leader Abu Bakr al Baghdadi.
Simpson had previously asked his readers on Twitter to follow an ISIS propagandist, whom later tweeted: "Allahu Akbar!!!! 2 of our brothers just opened fire."
Both Twitter accounts have been deactivated.
The posts show that modern terrorism is more loosely organized than ever. Groups like ISIS do not have the coordination and state sponsorship that Al Qaeda once did. Instead, like minded individuals find each other on the internet and attacks, while uncoordinated on a planning level, are claimed by the top level terror organization for propaganda wins.