The unsophisticated bomb that experts of Russia's Federal Security Service describe as possibly around 3kg of TNT blocks tied together, with all its volume and electric wires, could not be left unnoticed for long and therefore must have been laid under the rails right after the train had left the nearest station.
"An accomplice must have given a notice to the attackers to lay the bomb within minutes," he said, "The TNT power was enough to derail the train."
FSB operatives are questioning eyewitnesses, he said.
According to security services, the Grozny-Moscow train was bombed earlier this morning. Four carriages were derailed. Of 36 passengers who asked for medical aid, five, including one child, were hospitalized, said Oleg Atkov, a health official with the Russian national railways operator OAO RZD. Others were treated at the scene and arrived in Moscow at 11.30 a.m. by a commuter train.
"The explosion occurred under the locomotive, and a self-made remote control was found 50m from the railway," an official said.
