The Russian military truck was travelling towards the village of Galashki, in the republic of Ingushetia on Chechnya's western border, when it was blown up by a remote-controlled explosive device often used against federal troops by rebel guerrillas, the report said.

Channel One television said authorities had labeled the attack an act of terrorism, and opened a criminal inquiry.

"As a result of the explosion, five servicemen from the Russian defense ministry were killed and another hospitalized," an interior ministry official from Ingushetia told the RIA Novosti news agency.

Official statistics vary but up to 5,000 Russian troops and about 15,000 rebels are believed to have died since the current Chechen war began in October 1999.

The violence often spills over into the neighboring republics of Ingushetia and Dagestan, where large numbers of Chechens live and enjoy widespread support.

WAR.WIRE