Russians seek husband of Volgograd bus suicide bomb suspect

Russian investigators are delving into the background of a woman from the restive Caucasus region who is believed to have set off a suicide bomb aboard a crowded bus in the southern Russian city of Volgograd.

Six passengers and the bomber were killed in Monday's blast. Thirty-three people were injured.

Authorities identified the bomber as Naida Asiyalova, 30, from the Russian republic of Dagestan. They said she was believed to be the wife of a North Caucasus rebel whom she met in college and may have recruited to the separatist movement.

"This woman wearing a head scarf entered the bus at a bus stop, and shortly after an explosion happened," Vladimir Markin, spokesman for Russia's Investigative Committee, said. "This was confirmed by a woman who survived."

Asiyalova was four days shy of her 31st birthday, according to a passport found near the scene that shows her in a photograph wearing a black head scarf, and she was apparently very ill.

A page on a Russian social media website pleaded for donations to help her obtain medical treatment for a painful disease that had weakened her bones and left her dependent on painkillers and tranquillisers.

A news channel ran dramatic footage of the bus, moving at a high speed, first shaken by an impact, with flames shooting out from its right side, then engulfed in smoke as debris from the explosion flew in all directions.