SEOUL, Oct. 22 (Yonhap) -- A military aircraft believed to be from Russia violated South Korea's air defense identification zone over the East Sea on Tuesday, a government source said.
The plane entered the Korean Air Defense Identification Zone (KADIZ) over the East Sea earlier in the day, the source said, adding that F-15K fighter jets were scrambled to the area to force the planes to retreat.
The air defense zone was first drawn in 1951 by the U.S. Air Force during the 1950-53 Korean War to prevent air clashes between nations surrounding the Korean Peninsula. Last year, Seoul expanded it to counter China's unilateral decision to expand its own to cover a reef and other islands off the southern coast.
The air zone is not part of a country's air space and not bound by international law.