Terror chiefs have urged jihadists living in Britain and the US to carry out mass killings using “ghost guns”.
The call to arms came in the first edition of the group’s online Inspire magazine for four years.
MI5 believes it was published to coincide with the 20th anniversary of the 9/11 attacks.
Ghost guns are unregulated firearms bought online without the need for a security check.
They are often sold as kits with all the parts and equipment needed to build rifles and pistols.
Although they cannot be shipped directly into Britain, intelligence chiefs have said that there is nothing to stop terrorists from buying them in and posting them to the UK.
Inspire has claimed: “Operations performed by individuals and cells here and there over the whole world, without connections between them, have put intelligence apparatus in a state of confusion, as arresting the members of aborted cells does not influence the activities of others.”
Possession of the magazine in the UK without reasonable excuse is a terrorist offence.
The news comes as Mali’s government has denied that it plans to negotiate with jihadists, walking back an earlier statement from its religion ministry saying that it would do so.
In a statement published on social media on Thursday, the government in the Sahel state said that it had learned of plans for jihadist talks “through the press.”
The statement said: “No national or international organization has been officially mandated to carry out such an activity.”