Russian authorities said yesterday that a bomb blast was the likely reason for a train derailment on the railway line between Moscow and the former imperial capital Saint Petersburg in which 60 people were injured.
"According to preliminary information, the accident happened due to a planted handmade explosive device," state-owned Russian Railways said in a statement.
Russian Railways said that 12 carriages had been derailed in the incident late on Monday near Malaya Vishera in Novgorod Province, about 200km southeast of Saint Petersburg.
"Sixty people sought medical aid and 20 were taken to hospitals in the Novgorod region. Two are in critical condition," the statement said.
Prosecutors opened a criminal investigation into suspected terrorism, the Interfax news agency reported.
A local police source told RIA Novosti that "a bomb equivalent to 2km of TNT exploded on the rails." However another law enforcement source told Interfax that it was too early to be sure whether the derailment resulted from an attack.
Police sources said that a hole apparently caused by a blast had been found under the rails.
In addition to those taken to hospital in Novgorod, eight more people were taken to hospital in Saint Petersburg, including an Italian national with a broken arm and a 12-year-old girl suffering from a concussion.
The Moscow-Saint Petersburg train is popular with foreign tourists who head to see Saint Peterburg's cultural riches in large numbers.
Russia has seen a lull in insurgent attacks in its main population centers since a spate of suicide bombings in Moscow in 2003 and 2004 that were blamed on Chechen rebels.
But parts of the Russian Caucasus continue to experience insurgent violence and there has recently been an upsurge in the Ingushetia Province.
After Monday's derailment Russian Railways said that a total of 231 tickets had been sold for the train, while it carried 20 staff.