The Houses of Parliament in Westminster seen the day after an attack in London on March 23, 2017. Stefan Wermuth / Reuters

Less than 24 hours after British national Khalid Masood allegedly plowed a vehicle into bystanders on London’s Westminister Bridge and stabbed an officer outside the U.K. Parliament, the Islamic State took credit for the attack. In a statement released Thursday on Amaq, the ISIS propaganda arm, the group said the attacker was “a soldier of the Islamic State” who “carried out the operation in response to appeals targeting nationals of coalition countries,” referencing its call to attack citizens of countries fighting the group in Iraq and Syria.

The claim, which has been published in Arabic, German, and French, was not unlike previous statements the group has used to take responsibility for attacks. When it took credit for the Bastille Day attack in Nice last July, in which 86 people were killed, and the truck crash at a Berlin Christmas Market last December, in which 12 people were killed, the group offered similar wording by calling the attacker an ISIS “soldier” who targeted “citizens of the Crusader coalition.” In both cases, the group waited at least one day before claiming the attack and refrained from identifying the attacker by name, making it unclear if the group was aware of the individual’s identity before the attack took place.

Such behavior is typical of the Islamic State. As New York Times reporter Rukmini Callimachi noted Thursday, ISIS’s claim of responsibility followed its usual script and timeline. The group has, with few exceptions, consistently only claimed attacks it could prove it directed (as was the case of the Berlin market attack, for which it released a video of the attacker pledging allegiance to ISIS) or suggest it inspired (as in the case of Nice). Though the details surrounding the London attack are still emerging, ISIS has not yet released a video of Masood pledging allegiance, suggesting he may not have been directly commissioned.

But where there are similarities, there are also notable differences. As my colleague Uri Friedman noted, the attack in London targeted the highly guarded Westminster Palace, marking a departure from previous attacks, which have usually targeted less-secure areas. Also unlike past attacks, which the group has actively promoted, the assault in London was conspicuously absent from the latest issue of ISIS’s al-Naba newspaper, further suggesting the attack may not have been anticipated.

While some have suggested ISIS’s nearly 24-hour delay in claiming responsibility raises doubt over how directly it was actually involved in the London attack, versus simply claiming credit for an individual’s act of violence after the fact, the lull in information may have been intentional. As Charlie Winter noted in The Atlantic after last year’s attack in Brussels, claiming responsibility on its own time allowed ISIS to provoke speculation about the attack and, ultimately, command the media narrative surrounding it.

In the avalanche of uncertainty that followed the attacks, the ISIS propagandists were able to dictate their story—literally word for word—to an international, and specifically Western, audience. Releasing the claim of responsibility first in English was no mistake. Directed, first and foremost, at the Western enemies of ISIS, the statement was a way to capitalize on the international media storm surrounding Brussels that day. Be it through headlines or tweets, the propagandists manipulated a global audience, opponents and sympathizers alike, to disseminate their message of intimidation and enhance the perception of ISIS’s threat.

It’s still early, and more concrete evidence tying ISIS to the London attack could emerge later. But for now, observers are left with only the information released by authorities and ISIS’s word. And the uncertainty itself works in the group’s favor.

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