A bomb derailed a passenger train heading from the capital of restive Chechnya to Moscow today in what politicians saw as an attempt by separatist rebels to overshadow Russia's key national holiday.
The blast, which happened 90 miles south of Moscow left a three-feet-wide crater and derailed six carriages.
Interfax news agency quoted medical officials saying eight people had been taken to hospital with serious injuries while another 34 people suffered lighter injuries.
"According to the initial reports the train had been derailed by a blast of an explosive device equivalent to 3 kg (6.6 lb) of TNT," an rail spokesman said.
Officials also said that investigators had found wires leading to the crater and a remote control device 50 yards away. Interfax news agency earlier quoted deputy governor of the Moscow region Alexei Panteleyev saying the power of the bomb was equivalent to 5 kg (11 lb) of TNT.
Mr Panteleyev said the effect of the blast had been reduced because the bomb had been planted at a location where the railway line turns and trains slow down. "The slow speed of the train and effective brakes have averted a far worse catastrophe," he said.
No one has claimed responsibility for the blast, but most pro-Kremlin politicians are pointing to Chechen separatists. Some parliamentarians said the attack was probably timed to coincide with Russia's Day - a key national holiday.
"It is clear that by planning the terrorist act for today its authors wanted to deliver a blow on federal authorities," Interfax quoted pro-Kremlin parliament member Gennady Gudkov as saying.
On major holidays Russian security forces are routinely put on high alert for possible attacks by Chechen rebels.