Russia's domestic intelligence service says it has found the remains of an improvised explosive device at the site of a train derailment that killed at least 26 and injured nearly 100 people.
More than 90 people were injured when the high-speed train derailed
"We are indeed talking about a terrorist attack," Vladimir Markin, a spokesman for an investigative committee set up by Russia's FSB domestic intelligence service, told the Interfax news agency.
He said the committee had found fragments of a large bomb at the scene of the luxury train's crash.
FSB head Alexsander Bortnikov, reporting to Russian President Dmitry Medvedev in a televised meeting, said his investigators estimated the bomb packed the punch of seven kilograms (15 lbs.) of TNT.
The "Nevsky Express" was headed to St. Petersburg from Moscow when the last three cars went off the tracks about 350 kilometers (200 miles) from Moscow at 9:34 pm local time (6:34 pm UTC), on Friday, November 27.
661 passengers were on board at the time of the crash. Health Minister Tatyana Golikova said 96 people were injured and being treated in area hospitals.
A loud bang?
Around 95 survivors of the train wreck have been taken to local hospitals
Interfax news agency quoted an unnamed security official overnight who said that a crater about one meter (three feet) wide had been found near the scene, and that some passengers heard a loud bang before the derailment, prompting speculation about whether the crash was caused by a terrorist act.
Russian President Dmitry Medvedev has been kept informed about the derailment, which has delayed some 27,000 people as transport officials have been scambling to divert trains along other, often slower routes.
The same rail line was targeted in August 2007, when a bomb derailed a train, injuring 60 passengers. Russian prosecutors believed that an associate of a Chechen rebel leader was behind that attack.
Editor: Toma Tasovac