A terrorist act has been confirmed by the National Anti-terrorist Committee.

“Today at 2:05pm Moscow time [10:05 GMT] in Volgograd inside a bus, as a result of an unknown explosive device going off, a blast happened, leading to casualties,” a committee representative said in the statement.

The committee has reportedly identified the woman who was the suicide bomber.

The preliminary information said the bomber was the wife of a militant leader in Dagestan.

Also, a grenade has been found under the vehicle and it's now being checked whether the explosive is live, a source in the security forces now at the scene told RIA Novosti.

Forty passengers were on the bus. Seven of them are in critical condition. A 20-month-old toddler is among those injured. His state is assessed as moderately severe.

Russia’s Health Ministry indicated that most of the victims in the explosion sustained mine explosive-type wounds, caused by the bus’s paneling and the shattered glass.

Volgograd, formerly known as Stalingrad, is an important industrial city and the administrative center of Volgograd region located in the South of Russia.

NJF/NJF