Investigators say a suicide bomber has struck a passenger bus in the Russian city of Volgograd, killing six people and injuring at least 20 others. About 40 people were onboard the bus at the time of the explosion.
The state ITAR-Tass news agency reported Monday that Valery Safonov, an official with Russia's main investigative agency, had called the suspected bomber a militant. Officials identified her as 30-year-old Naida Asiyalova from Dagestan.
"A criminal case has been opened under articles outlining terrorism, murder and the illegal use of firearms," Investigative Committee spokesman Vladimir Markin told the RIA Novosti news agency.
Officials said the blast occurred at about 2 p.m. (1000 UTC) in the Volga River city of Volgograd, about 900 kilometers (560 miles) southeast of Moscow. The Interfax news agency reported that investigators found identity documents belonging to the suspected bomber near the site and that they believe her the wife of an Islamic militant.
Early reports had proved a bit less reliable as the situation developed. Russia's National Anti-Terrorism Committee had issued a statement shortly after the blast confirming at the time that it was caused by an "unidentified explosive device." However, Russia's state-run news channel RIA had reported that preliminary information suggested it was caused by a problem with a gas canister.
Volgograd lies north of the restive North Caucasus, a string of provinces where the government is attempting to quell an Islamist insurgency. In 2008, a female suicide bomber blew up a bus in the North Caucasus. No group has so far come forward to claim responsibility for the bombing or give a motive.
mkg/dr (Reuters, AFP, dpa, AP)