Seoul - South Korea's military said on Thursday one of its planes had flown through China's newly-declared air defence zone in the East China Sea without informing Beijing.
The flight on Tuesday was part of a regular military surveillance exercise around a disputed, submerged, South Korean controlled rock, known as Ieodo that has long been a source of diplomatic tension with Beijing.
"We did not notify China," a defence ministry spokesperson said.
China unilaterally declared a new "air defence identification zone" on Saturday over an area that includes Ieodo, as well as a set of islands at the centre of a tense territorial dispute between China and Japan.
Both Tokyo and Seoul have rejected China's demand that all aircraft traversing the zone file flight plans and ID details, and two US B-52 bombers flew through the area on Monday without complying.
The South Korean spokesperson said military planes would continue to fly over the Ieodo area without providing any notification to China.