MOSCOW, July 24 (Xinhuanet) -- A bomb exploded under a commuter train early Sunday morning in Russia's southern Dagestan republic, killing one person and injuring four others aboard, police said.

   

A bomb exploded under a commuter train early Sunday morning in Russia's southern Dagestan republic, killing one person and injuring four others aboard, police said. (Xinhua/AFP photo)

 The attack, which hit the first carriage of a train running from the regional capital of Makhachkala to the town of Khasavyurt, killed a 20-year-old woman and injured four others, Khasavyurt police told the Interfax news agency.

    The train was on its first morning run and carried only 16 passengers. Some of its carriages were derailed, local railway police told Interfax.

    The bomb, which experts said was equivalent to 11 kg of TNT, left a crater two meters deep and two and a half meters wide on the track bed.

    Regional prosecutors have opened a criminal inquiry into the blast, which they believed was a terrorist attack.

    Dagestan is an impoverished region neighboring Chechnya where the fighting between government forces and separatist rebels has spilled over into nearby regions including Dagestan.

    A similar railway explosion hit Dagestan on June 25, derailing an engineering train and injuring two people. Enditem