Isis 'kills five Russian hostages' accused of spying against militant group

Chechen officials have identified a man dubbed 'Russia's Jihadi John', seen in a previous video apparently murdering his countryman

Isis has executed five more Russian nationals after accusing them of "spying" in its territories, according to Russian media reports.

Last week, a video was released by the militant group showing a man dubbed the Russian "Jihadi John" purportedly executing a "Chechen spy".

The executioner has been identified by officials in the North Caucasus as Anatoly Zemlyanka. The Chechen leader Ramzan Kadyrov reportedly wrote on Instagram that the 28-year-old was an ethnic Russian and wanted by the police.

And on Tuesday, LifeNews quoted security sources in the region as saying another five Russians had been executed by Isis on similar charges. Their identities are unknown.

New figures released by the New York-based Soufan Group suggested Russians were travelling to join Isis in their droves, with numbers of foreign fighters from the federation and central Asia up three-fold in the past year.

With an estimated 2,400 foreign fighters, Russia was reported to be the third-largest contributor to Isis's ranks, behind only Tunisia and Saudi Arabia.

The Soufan Group said the increase in Russia was "far more substantial proportionately than that seen in Western Europe over the same time span", the Daily Beast reported.

And while many travel over to join Isis from areas in the North Caucasus with large Muslim populations, a report in the Novaya Gazeta suggested Russia's secret services were facilitating this - effectively exporting the country's worst extremists abroad.

Little is known about Mr Zemlyanka himself, who became one of the most wanted men in Russia when he beheaded countryman Magomed Khasiev in Syria last week.

Russian media reports have described him of the son of an Orthodox Christian mother, growing up in a remote community in Noyabrsk, Siberia.