How does Isis claim responsibility for attacks?

In each attack, the initial claim is made by the jihadist group's Amaq news agency via the social media app Telegram.

The claim typically comes a day after the attack, when evidence has emerged the attacker or attackers were inspired by Isis, though it is not uncommon for it to come days or even weeks later.

The initial claim follows a standard format, with the attacker glorified as a "soldier of the Islamic State" in a statement saying the attack was carried out in "response to calls to target citizens of coalition countries".

After the initial claim, Amaq will often release video, audio or text of the perpetrators pledging bayat or allegiance to the so-called Islamic State's "caliph" Abu Bakr al-Baghdadi.

"Later, as if to provide rejoinders to analysts and news commentators who questioned the veracity of Amaq’s reports, the group has often extolled terrorists responsible for these attacks in publications like Dabiq and Rumiyah, as well as in videos," terrorism analyst Michael S Smith II told The Independent.

Mr Smith described how one claim even included a screenshot of a tweet in which a terrorist and his coconspirator pledged allegiance to al-Baghdadi. The group's propaganda has asked supporters to leave behind notes of support for the group before they carry out attacks.

"Each of these weaves together a larger picture on how Isis seeks to claim attacks and then fetishes their fighter imagery for years," Chris Sampson, cyber and terror analyst for TAPSTRI, said. "They parade each of these attacks as their message of victory."

However, while Isis are often accurate in identifying who carried out the attack, they are less accurate with the details.