A Chinese Air Force colonel flew his MIG-21 jet across the Yellow Sea and defected to South Korea to seek asylum in ''a third country,'' a South Korean spokesman said.
Officials originally believed the jet was part of a possible North Korean invasion and issued the first air attack warning over the capital of Seoul since the end of the Korean war in 1953. The warning was lifted after 17 minutes.
On Friday, South Korea's military forces sank an alleged North Korean spy ship off the South's east coast, killing four commandos on board. A second suspected spy vessel got away on Saturday, a military spokesman said.