The fierce battle, which involved machine gun fire and grenades, shocked people living in Baku, triggered warnings from the authorities of a rise in violence linked to extremists and threatened to damage Azerbaijan’s relations with neighbouring Iran.

Although they didn’t explicitly link violence to IS in Syria, the authorities have been increasingly nervous of IS recruitment in Azerbaijan.

In a statement Azerbaijan’s prosecutor-general said that the group, called the Muslim Unity Movement was planning various attacks across Baku and that they had links to Islamic extremists.

“These people and their supporters gathered in Baku and other regions, stocked with various types of weapons, ammunition, explosives,” the prosecutor-general said.

“During the operation, the gang showed armed resistance to police officers and started firing automatic weapons, hand grenades were also thrown.”

The prosecutor-general also said that 14 so called gang members were arrested during the raid in the village of Nardaran.

But neighbouring Iran viewed the incident differently.

The men who were killed were Shia Muslims. Azerbaijan is officially a secular country and the authorities have previously cracked-down on the Shia community, much to the irrita- tion of Iran. The Iranian official media was scathing of the Azerbaijani authorities’explanation.

The Iranian-state owned PressTV described the violence as a crackdown on Azerbaijan’s Shia Muslims.

“The attack came as Shias gathered for a religious ceremony in the village of Nardaran to mark Arabaeen, December 2, the 40th day since the death of Imam Hussein and his followers in a battle of Karbala,” it said. “The reports said violence erupted when security forces attempted to arrest Tale’ Bagirzade, the leader of the MMU, who was delivering a speech on the occasion.”