Russian experts have found no proof of North Korea’s involvement in the sinking of a South Korean warship, a source close to the Russian Navy General Headquarters told Interfax on Tuesday.

In a move initiated by President Dmitry Medvedev, a group of Russian defense experts arrived in South Korea last week to examine the wreckage of a torpedo allegedly fired at the Cheonan corvette by a North Korean submarine in late March.

The Cheonan sunk on March 26 in the Yellow Sea near the disputed maritime border between the two Koreas. An international investigation then concluded that the vessel was sunk by a torpedo fired from a North Korean submarine in an attack that killed 46 sailors, which is vehemently opposed by Pyongyang.