At least seven people are now known to have died in the bombing of a theatre in the Russian city of Stavropol yesterday.
The powerful blast came just before the start of a dance show given by a Chechen traditional dance troupe.
Stavropol is an ethnically Russian city close to several Muslim republics in the volatile North Caucasus region. It has been largely free of terrorist-related violence in recent years but has experienced Islamist attacks in the past.
The Stavropol region was recently integrated into the North Caucasus Federal District, with the Kremlin hoping the administrative change would help tackle violent separatist and Islamist insurgencies in Chechnya, Dagestan and Ingushetia.
Along with the seven people killed by yesterday’s bombing, more than 40 people were injured and 16 of them are said to be in a critical condition.
Moscow has begun a criminal investigation under terrorism laws as it hunts those responsible.