Russian bus bombing kills 8

MOSCOW, Russia (CNN) -- Eight people were killed and 56 wounded when a bomb exploded on a bus in central Russia Wednesday, the country's state-run RTR television station reported.

The Interfax news agency reported 42 people were hospitalized and seven of those were in critical condition.

The bombing happened at about 8 a.m. as people were traveling to work in the city of Togliatti, the TV reports said.

Pictures from the scene showed a gray bus partly destroyed, with its windows blown out.

Russian TV reported the explosion involved about 1.5 kilos (3 pounds) of TNT.

Investigators were trying to determine if a passenger had carried on the explosive device or whether it had been planted on the vehicle, according to Russian news agencies.

Andrei Derbenev, a spokesman for the Togliatti rescue service, told ITAR-Tass agency the powerful blast shattered windows on nearby residential buildings. E-mail to a friend

CNN Producer Igor Malakhov contributed to this report.

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