By Sarah Rainsford BBC Moscow correspondent

Russian helicopters are frequently targeted by separatists

The Russian military has confirmed that one man was killed and two seriously injured after a helicopter came down in Chechnya on Thursday evening.

Unconfirmed reports suggest it was shot down by Chechen rebels.

Meanwhile the conflict between Russian troops and separatists in Chechnya has spilled over the border once again.

An ambush on a military convoy in neighbouring Ingushetia has left six Russian soldiers dead and seven injured.

The Mi-8 helicopter came down in a mountainous region in south eastern Chechnya.

It is an area known as a rebel stronghold.

It was originally thought all three crew members had died instantly, but two men have now been rescued and evacuated to hospital with serious injuries.

Immediately after the crash a spokesman said the helicopter had been shot down by a shoulder-fired missile.

The military now suggest the crew may simply have crashed in poor weather.

Separatist resolve

Over the border in Ingushetia, events are clearer - a military convoy came under heavy fire there on Thursday evening.

The troops were en route from Grozny to base, just across the Chechen border.

Six soldiers died on the spot.

The Russian military has been targeted in Ingushetia before. Just last week, five soldiers were killed when their convoy hit a mine.