Volgograd must have experienced another terror attack, a source in the region's law enforcement reports.

"The explosion in the Volgograd trolley-bus was most likely an act of terrorism resembling two previous ones - in the bus and at the railway station," the source said.

There was an explosion in a trolley-bus in Dzerzhinsky district of Volgograd Monday morning in which at least ten people died.

The report was confirmed to Interfax at the Interior Ministry and the Investigative Committee of Russia.

"So far we can confirm that there was an explosion in a trolley-bus in Volgograd and ten people died," Interfax was told at the Interior Ministry press center.

Meanwhile, the Investigative Committee reported that people were injured in the explosion.

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