Five perpetrators were detained by the FSB, with assistance of the local police, in the town of Pallasovsk, Volgograd Region, the security agency said.

The detained were members of the so-called 'Pallasovsky Jamaat' group, which “was involved in recruitment… of residents of the region to participate in activities of Islamic State [IS, formerly ISIS] international terrorist organization,” the FSB added.

According to the agency, one of the members of the group “planned to stage a terror attack in the [Volgograd] region.”

© The Federal Security Service of the Russian Federation

“Ammunition, explosives as well as other chemical compounds and striking elements for improvised explosive devices, literature of religious and extremist nature were found and seized at their place of residence,” the FSB said in the statement.

A criminal case “on organization of an illegal armed group or participation in one” has been launched against the detained Pallasovsky Jamaat members.

Volgograd, formerly Stalingrad, is a city of around 1 million people on the Volga River, not far from Russia's volatile North Caucasus region, has seen a series of suicide attacks in the past three years.

In October 2013, a terrorist blew herself up on a bus, killing six people and injuring more than 30 others.

On December 29 of the same year, 18 people died and 44 were wounded at the Volgograd train station in another suicide blast.

The next day, an explosion rocked a trolleybus, killing 15 passengers and injuring over 30 others.