Paris (AFP) - Seven attacks in a week, afflicting every corner of the world: whether they organised, guided or just inspired them, the Islamic State (IS) group has developed a finely-tuned machine for claiming responsibility, analysts say.
From Manchester to Melbourne, via Somalia, Indonesia, Egypt, Manila and London, the week of May 29 to June 5 saw a series of deadly strikes claimed by the jihadist group, mostly via its "news agency" Amaq.
While it tries to present itself online as an international media agency, including with "Breaking News" straps and neutral news vocabulary, Amaq is first and foremost a propaganda tool.
But for the moment it has not been caught red-handed touting untruths, and its claims are considered as reliable by experts and anti-terrorism authorities.
"The growing number of claims in recent days fits in with the growing number of attacks," Mathieu Guidere, an expert on Islamist movements, told AFP.
These claims always correspond to attacks inspired, guided or organised by the Islamic State "because they can't allow themselves to lie about a case, or to take responsibility for attacks which were not carried out in their name," said Guidere.
"If that were the case, they would be the laughing stock of the jihadist world. Their credibility is at stake."
- No false claims -
US expert Thomas Jocelyn of the Foundation for Defense of Democracies in Washington added: "Generally speaking, when they claim an attack, we don't know of any blatantly false claim.
"They may exaggerate or have some problems in the claim, but we don't know of anything that they have claimed, specially in the West, that has been clearly wrong."
At the height of the self-proclaimed caliphate in Syria and Iraq, the group's communication was centralised and put under the control of the powerful IS chiefs -- but it is now more decentralised and therefore quicker, Guidere suggested.
"A new way of releasing claims has been introduced," he said.
"Previously they needed the approval of the central command; now, because they are losing ground on all fronts there are decentralised correspondents of Amaq who are able to make claims in the name of IS," added Guidere.
"They called on all their supporters, around the world, to launch attacks to show they are not finished, despite their setbacks on the ground in Syria and in Iraq," he added.
"They want to prove that they remain active outside the caliphate's borders, and that the potential number of fighters outside is bigger than what there is inside."
- 'Martyr' message -
Amaq was set up by the Islamic State to replace the Twitter accounts that they used before and which were shut down, according to Romain Caillet, a French consultant on Islamist issues.
In order to credibly claim an attack there must be some kind of evidence, even if only an email exchange, or a suicide "martyr" message to link the jihadist to IS, he said.
"Either they planned the attack directly, or they have enough information to be sure that they guided or inspired the author of the attack. It can be a video, an exchange of messages. There must have been a contact," he said.
The internal workings of Amaq, like other media controlled by IS, remains somewhat mysterious, despite some insights gleaned from members of the group who either defected or were arrested and interrogated
They describe an important organisation within IS that is considered crucial by its chiefs and has significant resources.
Last week, social media announced the death in Syria, in a bombardment by the US-led international coalition, of one of the founders of Amaq, Syrian Rayan Machaal, a former revolutionary from Aleppo who switched to IS in late 2013.
There has been no confirmation of his death so far.
On Tuesday in Paris a man was shot and injured after attacking a police officer outside the world-famous Notre Dame Cathedral, shouting "This is for Syria". He also pledged allegiance to IS in a video found in the apartment he was renting.
Some 24 hours after the attack there was still no claim from IS itself of responsibility for the attack, via Amaq or elsewhere.