Who is thought to be behind the Moscow attack?

The name comes from that given to a region by some local Islamic rulers and so explicitly rejects modern national frontiers while evoking what its members consider the lost glory and power of Muslim empires.

It was formed at the peak of the expansion of IS in 2015 when the Iraq- and Syria-based group was trying to expand by building a network of affiliates through the Middle East, the Maghreb, west Asia and other parts of Africa.

The group was also responsible for a hugely destructive attack on Kabul’s international airport in 2021 that killed 13 US troops and more than 150 civilians during the chaotic US evacuation from the country.

Earlier this year, the US intercepted communications confirming the group had carried out twin bombings in Iran that killed nearly 100 people – though ISKP did not claim responsibility.

Sometimes a new leader brings a personal agenda, other times launching long-range international attacks is seen as a way to attract new recruits, win new resources from sponsors or mobilise followers otherwise disillusioned by local failures.

Michael Kugelman, of the Washington-based Wilson Center, said ISKP “sees Russia as being complicit in activities that regularly oppress Muslims” and counts as members a number of central Asian militants with their own grievances against Moscow.