South Korea and Russia have failed to identify the exact cause of last year's failed launch of Korea's Naro space rocket, dimming the prospect of a third launch this year.

The Education, Science and Technology Ministry said on Monday that the fourth Failure Review Board (FRB) meeting held in Russia last week looked into the possibility of a malfunction of an oxidizer tank and checked on a separator for the first and second stage rockets, but no decisive clue was discovered.

The ministry said that the two sides are continuing their efforts to determine the exact cause of the launch failure and will take proper measures to improve the next attempt.