All 118 crew members were killed

It is not known how many bodies were destroyed by the two mysterious explosions which ripped through the Kursk on 12 August, killing all 118 sailors on board.

Divers could face grave danger trying to get onto the sub, not only from the intense cold and darkness 108 metres (355 feet) down, but also from jagged metal debris inside the wreck that could puncture their survival suits.

Norwegian-Russian mission

Birger Haraldseid from the oil firm Halliburton said Norwegian divers would do most of the survey work and drilling, but only a Russian military diver would go inside the Kursk if it was considered safe to do so.

A mini-sub explored the wreck on Friday, and initial radiation checks proved negative.

Senior Russian naval officials have cautioned that the whole operation may be called off if it threatens the divers' lives.

A spokesman for the Northern Fleet, Vladimir Navrotsky, told the Russian Interfax news agency that four Russian divers and two Norwegians were working to cut through the vessel's outer armour around its rescue hatch.

The Norwegian diving platform Regalia was positioned over the wreck on Friday.

Eighteen Russian, Norwegian and British divers will be involved in the recovery of bodies, which will begin in earnest on Tuesday or Wednesday, Mr Navrotsky said.

President Putin's role

Victims' relatives have urged Russian President Vladimir Putin not to risk divers' lives rushing an operation to raise the bodies.

Grieving relatives: There was fury at the delay in the rescue mission

President Putin gave the go-ahead last month for the recovery mission.

Experts in charge of the mission say only 20% to 30% of the bodies are likely to be recovered.

The Russian authorities came under a torrent of criticism from bereaved relatives and the Russian media for failing to give accurate information when the Kursk sank.