Russia says blasts led to deadly train crashes in regions bordering Ukraine

Investigators say explosions' caused two bridges to collapse, triggering derailments and at least seven deaths

Russian investigators said they believed explosions" had caused two bridges in the border regions of Kursk and Bryansk to collapse overnight, derailing trains, killing at least seven people and injuring dozens.

In Bryansk, which borders Ukraine, a road bridge collapsed on to a railway line late on Saturday, derailing a passenger train heading to Moscow and killing at least seven people. A rail bridge in neighbouring Kursk also collapsed overnight, derailing a freight train and injuring the driver, officials said. Kursk also borders Ukraine.