A South Korean general was sacked for a lapse in border security after a fishing boat from North Korea managed to cross the intensely monitored sea between the countries and dock undetected.
The military failed to identify the small wooden boat - carrying four North Korean fishermen - until a civilian alerted the police after it arrived at a port roughly 257 kilometers east of Seoul on June 15.
Two of the passengers defected to the South, while the other two chose to return to North Korea.
General Lee Jin Sung was fired after an investigation, Defense Minister Jeong Kyeong Doo said.
"Under no circumstances is failed military surveillance acceptable," Jeong said.