North Korea gunned down a South Korean official who drifted into it's waters and burned his body.
According to Seoul, the man worked for the fisheries department and had disappeared from a patrol boat near the border. His burned body was later found in the North's waters.
North Korean soldiers shot him, then poured oil over his body and set it alight, the ministry said.
At a news conference reported on by BBC, South Korea's defense ministry said it "strongly condemned such a brutal act and strongly urged the North to provide an explanation and punish those responsible."