Russian salvage ships have begun a final expedition to recover the remaining fragments of the Kursk submarine from the bed of the Barents Sea.

We are planning to do the job in a week or two, weather permitting

Vladimir Dobroskochenko Vice Admiral

The mission has been delayed for more than a fortnight due to fierce winds and high seas. If current weather conditions now hold, the operation is expected to take around two weeks.

Russian investigators say the fragments may contain the crucial clues as to what caused the nuclear submarine to explode and sink nearly two years ago, killing all 118 people on board.

The bulk of the submarine was recovered last autumn, but the nose was left on the sea bed as it was considered to be too unstable to raise. Other remains were also left as they were judged too sensitive for foreign eyes.

Investigators have already declared that sections deemed irrelevant to the inquiry will be destroyed on the sea bed.

Waiting for answers

A preliminary report by the Russian navy concluded that the Kursk sank when its own torpedoes exploded, perhaps because they were using a particularly volatile form of fuel.

This has never been confirmed, but other explanations such as a collision with a foreign vessel have been ruled out.

Officials have promised to issue a final conclusion, long awaited by relatives of the 118 men, after the fragments are lifted.

Three bodies have never been retrieved from the site, but specialists dismantling parts of the Kursk already recovered have said they have found human remains inside the tangled metal.