"A source from the Sunzhensky region interior ministry said around 50 soldiers were killed," the Ingushetia.org website reported.

Convoy destroyed

A regional law enforcement official told the Reuters news agency that three armoured personnel carriers and two lorries were hit by automatic-rifle fire and grenades killing all but one soldier travelling in the convoy.

"The soldiers didn't even manage to resist, because several rocket-propelled grenades hit their trucks," the source said.

A resident of the Muzhichi told Reuters that troops had barricaded the village and were checking passports while two helicopters circled overhead.

Moscow is struggling to control Ingushetia - a poor, predominantly Muslim province - which has seen increasing numbers of bombings and clashes between federal troops and local armed groups.  

The local branch of human rights group Memorial says that 93 people, from a population of 470,000, were killed in violence in the first eight months of the year.

Russian officials blame the violence on groups of armed men, many driven by Islamist ideas, who they say have tried to overthrow Moscow's rule since 2002.

Locals and human rights groups have criticised heavy-handed tactics by the security forces, which along with poverty and official corruption have created a groundswell of popular opposition to Moscow-backed officials.

In a separate incident on Saturday, a car exploded in the village of Kantyshevo killing its driver in what reports quoted officials as saying could be the accidental detonation of a bomb intended for "a terrorist attack".