Russian investigators have arrived in Seoul to conduct an independent investigation into the events which led to the sinking of a South Korean warship in March this year.
An international team of investigators had earlier blamed North Korea, saying one of its submarines fired a torpedo that sank the corvette, killing 46 on board.
Pyongyang has denied the allegations and the findings themselves have been widely questioned by China.
The Russian team, which includes torpedo and submarine engineers, hopes to reveal its findings next week.
If they support the conclusions reached by Seoul, it could convince China to support UN sanctions against Pyongyang.
However, Pavel Leshakov, an expert on Korean studies from Moscow State University, says Russia has many reasons to doubt the outcome of the original investigation.
The incident has destabilized the region with large scale military exercises being held both on land and at sea following the North's warning that war could break out at any moment.