Two servicemen had been killed and three others wounded in explosion, in Dagestan, Friday, Dagestani Interior Ministry, said to The ITAR-Tass news agency.
However, the RIA-Novosti and Interfax news agencies quoted medical officials as saying that one soldier had been killed and six wounded.
RIA-Novosti said the blast occurred near a trolley bus terminus in the capital, Makhachkala.
"I can confirm there was an explosion, but I have no other details," a local interior ministry spokesman told Reuters.
Earlier reports suggested a truck had exploded, but a Reuters witness at the scene said there was no evidence of a vehicle. Soldiers from the barracks said the blast occurred during routine checks for explosive devices in the street.
The explosion happened at a sensitive time for Russia, which is marking the first anniversary of the attack by pro-Chechen militants on a school in Beslan, North Ossetia, that resulted in 331 people being killed.
Photo: RIA Novosti