South Korea urged North Korea on Saturday to further investigate the fatal shooting of a South Korean fisheries official and suggested it could be an unprecedented joint probe by the two sides, as public and political outrage over the killing grew.

The move came as a rare apology from North Korean leader Kim Jong Un appears to have failed to soothe criticism over the Moon Jae-in administration's handling of the accident.

After a National Security Council meeting Friday evening, South Korea's presidential office said it would call for a joint probe into the case with North Korea if needed, saying there were discrepancies in accounts of the accident from the two sides.