10 killed in Russia bus explosion

At least 10 people were killed and 10 were injured early Monday when an explosion hit a trolley bus in Russia's Volgograd city, the second fatal blast within two days.

Russian Investigation Committee spokesman Vladimir Markin said the explosion could also be a terror attack, resembling the Sunday blast at the city's railway station that left at least 16 dead and more than 40 injured.

A criminal case under the act of terrorism and illegal turnover of explosives has been opened.

The emergency situations ministry has sent a plane with medical modules on board to attend the victims of the explosion.