A Japanese reconnaissance plane approached South Korea's de-facto airspace over the East Sea Wednesday but turned back after warnings from the South's air force, officials said Thursday.
The RF-4C plane from Japan's Self Defense Force came as close as 10 miles to the South's Korea Air Defense Identification Zone, a military buffer zone surrounding the country's airspace, around 12:20 p.m., officials at the Joint Chiefs of Staff said.
The area was near Dokdo, a group of rocky islets that Japan claims sovereignty over.
The Japanese plane turned back at 12:25 p.m. after receiving radio warnings from the South's air force three times, officials said.
At that time, two South Korean F-4 fighter jets were patrolling a nearby region and were ordered to move to the Dokdo area, but there was no confrontation, officials said.
The incident came amid high tension between the two countries over Japan's claim to Dokdo, called Takeshima in Japan.
Just hours before the incident, a provincial assembly in Japan voted to designate a day on its calendar to promote its claim over the islets, sparking strong protests from South Korea.
There were two similar instances of Japanese aircraft approaching South Korean airspace without permission recently.
On March 8, a light plane from Japan's Asahi Shimnun newspaper attempted to enter the area over Dokdo, prompting South Korean jet fighters to be scrambled. The following day, a patrol plane from Japan's Coast Guard also came close to the South's airspace.