A passenger train traveling from the rebel republic of Chechnya to Moscow derailed after an explosion, in what Russian officials said was an act of terrorism that slightly injured dozens of people on board.

"This was a terrorist attack," Alexei Panteleyev, the deputy governor of the Moscow region, was quoted as saying by RIA Novosti news agency hours after the incident, which coincided with the annual national independence day holiday in Russia.

There were no reported fatalities but five people were hospitalized with injuries and 37 others sought medical attention after five cars jumped the tracks near the town of Uzunovo about 150 kilometers (93 miles) southeast of Moscow, according to Russian media reports.

None of the reported injuries was life-threatening.

Deputy Prosecutor General Nikolai Savchenko said an investigation had been opened for suspected "terrorism and attempted murder of two or more people." There was no claim of responsibility for the attack, and police said they were searching the nearby area for the perpetrator.

Most of the injured were treated at the scene and released while the remaining passengers boarded another train and continued their journey to Moscow.

A spokeswoman for the FSB security service said the train's conductor reported seeing an explosion on the tracks ahead of him seconds before the train derailed.

Investigators also found evidence, including electric cables wired to one of the rails and a location beside the tracks where the "supposed criminal" hid before detonating the blast, indicating that the blast was set off deliberately, she said.

The train was travelling at a slow speed when the derailment occurred and Echo Moskvi radio said the conductor had time to apply the brakes after he saw the explosion and before the cars jumped the tracks.

"It all happened very quickly," an unidentified elderly woman who was aboard the train said in an interview with the NTV television network. "There was a loud noise. I didn't know what was happening."

The blast had a force equivalent to three kilograms of TNT and left a crater about one meter (three feet) wide on the path of the railway, officials said.

Investigators from several federal agencies including the FSB, the interior ministry and the emergency situations ministry travelled to the scene and Savchenko said they checked the surrounding area to verify that no other explosive devices had been planted nearby.

The derailment came amid heightened fears that Chechen rebels may carry out more attacks during the summer holiday season.

A senior law enforcement official said last Wednesday that security was being stepped up at airports, train stations and other public sites under measures to prevent acts of terrorism and other crimes during the summer.

Those measures included stationing of police officers with special training in profiling criminal suspects based on behavioral and physical traits, First Deputy Interior Minister Alexander Chekalin was quoted by ITAR-TASS news agency as saying.

Russian troops have been fighting separatist rebel forces in Chechnya for the past five and a half years, the second war Russia has fought in Chechnya in the past decade.

Chechen rebels have in the past claimed responsibility for attacks on Russian transport facilities, including the simultaneous downing last August of two passenger jets followed a week later by a suicide bomb attack outside a busy Moscow metro station.

(Chinadaily.com via agencies June 13, 2005)