South Korean fighters were scrambled to intercept six Russian warplanes that intruded its Korean Air Defense Identification Zone (KADIZ) on Tuesday.
An A-50 early-warning aircraft, three SU-27 fighter jets and two TU-95 bombers entered the KADIZ four times without prior notice. Seoul deployed around 10 fighters, including F-15K and KF-16 jets to track and send warning messages to force them out, Yonhap reported Tuesday.
The aircraft stayed in the zone for about four hours in total before leaving, the Joint Chiefs of Staff (JCS) said.
The warplanes breached the KADIZ over waters surrounding the Korean Peninsula, including the country's easternmost islets of Dokdo and the island of Ulleung in the East Sea; above the southern city of Pohang and the island of Jeju and areas in the Yellow Sea.
But none of the aircraft violated South Korea's territorial airspace, the JCS said.
Earlier this month, reports suggested that South Korea was planning to sign an agreement to establish a direct military hotline with Russia in order to share military flight information and prevent any accidental airspace violation by month-end.
The latest violation brought the total number of entries by Russian aircraft into KADIZ so far this year to 20.
Following the incident, the defense ministry lodged a strong complaint with Russia, and urged Russia to come up with measures to prevent recurrences, according to ministry officials.