By Paul Wood on the Chechen border

The BBC has been shown fresh evidence to substantiate allegations made by Chechen villagers of a massacre of some 41 civilians by Russian troops in early December.

After initially denying that anything happened in the village of Alkhan-Yurt, the Russian defence ministry now says it has opened an investigation into the incident.

An investigation is underway "in Alkhan-Yurt to verify the information on the massacre of civilians," a defence ministry spokesman told the French news agency Agence-France Presse, speaking on condition of anonymity.

Russian Deputy Prime Minister Nikolay Koshman can be seen captured on amateur video tape angrily upbraiding army officers in the village.

"You'll be held personally responsible for this", he tells one officer, who appears to hold the rank of lieutenant colonel. "I've never seen anything like it anywhere in Chechnya."

The villagers claim that 41 civilians were killed, and Mr Koshman is given documents containing a list of the dead, their names, and how they died.

"There are eyewitnesses," he says, handing the papers to a man identified as a military prosecutor.

Looting

The film also shows piles of stolen goods which have been loaded into Russian vehicles - video recorders, carpets, crockery, an album of family photographs spattered with blood.

The villagers say that many of those who died were shot after they tried to stop looting by drunken soldiers.

The video was taken by a cameraman working for Malik Saidulayev, a millionaire Chechen businessman who is an ally of Moscow against the Islamic hard-liners, but whose home is in Alkhan-Yurt.

He has now declared he will run for the presidency of Chechnya after the war.

Some observers think that he is publicising this damaging material to boost his popularity by showing he can stand up to Russian excesses.

As the group goes around the village, a Russian soldier shouts out, "We will shoot you".

He does not recognise Mr Koshman or the Russian generals included in the group.

"Don't you know this is a deputy-premier of Russia? How dare you behave like this?" a furious general tells him, before stripping him of his identity papers and sending him for questioning at military headquarters.

On the tape Mr Koshman says he will personally inform Prime Minister Vladimir Putin himself about what has happened in Alkhan-Yurt.

The Chechens now say they have been told that 17 soldiers have been arrested, including two colonels.