(CNN) -- An explosion hit a trolleybus in the Russian city of Volgograd on Monday, killing at least 10 people, the state-run news agency RIA Novosti reported.
The trolleybus blast took place the day after an explosion at a train station in Volgograd killed 17 people.
Russian federal investigators say they suspect a female suicide bomber caused the Sunday blast in the train station, which wounded at least 34 people.
The deadly explosions come less than six weeks ahead of the Winter Olympics in Sochi, which is situated less than 1,000 kilometers (620 miles) from Volgograd.
