A South Korean company claiming to have found a sunken Russian warship has seen its shares soar and then fall on the stock market amid rumours the vessel was carrying a cargo of gold.

The Seoul-based Shinil Group said on Monday its divers had discovered the Dmitri Donskoi, which sank off an eastern Korean island during the Russo-Japanese war.

It says it will try and raise the ship which was said to be carrying 200 tons of gold when it foundered in 1905 but there has been some scepticism about the claim.

The unlisted Shinil was founded on June 1 and its president recently agreed to acquire shares in local company Jeil Steel.

Jeil’s stock prices sharply rose after Shinil’s claim before they dropped more than 20% after Thursday’s trading.

The Financial Supervisory Service says it is closely monitoring trade activity involving the shares of Jeil Steel.