Russia is still cleaning up in the aftermath of a bomb that exploded outside the Southern Russian city of Volgograd on Monday.
A female suicide bomber is believed to have triggered the blast on a bus, killing six people and injuring 30 others.
President Vladimir Putin travelled to the Russian city of Ufa on Tuesday to meet with Muslim clerics.
He took the opportunity to warn unspecified foreign rivals not to use Islam to weaken the Russian state: “Some political forces use Islam – the radicals within it who are not typical of Russian Muslims – to weaken our state and create conflicts on Russian soil that can then be controlled from abroad.”
Security drills have begun already for the 2014 Winter Olympics that will take place next February in Sochi. The Black sea resort is not far from Volgograd, the scene of Monday’s bombing.