A train has been derailed by a bomb in the southern Russian republic of Dagestan. The driver and his assistant were injured in the blast on the line between Kurush and Karlan-Yurt in the centre of the region. A criminal investigation has been opened. Nobody has claimed responsibility but the incident has been linked to the conflict in Chechnya which borders Dagestan to the west. The republic has seen several militant attacks in the last few months. Meanwhile, another bomb went off on Saturday morning near a school in the town of Khassaviourt. Nobody was injured. And two devices exploded overnight on the outskirts of Dagestan’s capital Makhachkala. Six police officers were wounded.