The Tu-95 bombers entered the KADIZ without prior notice above the East Sea once at around 3:37 a.m. and stayed in the zone for about 29 minutes, according to the source.
|A Russian warplanes that violated Japan's air defense zone on Thursday captured by Japan Air Self-Defense Force on Thursday. (Yonhap)|
The Air Force, in response, deployed multiple jets, including F-15Ks, to track them and send warning messages in accordance with its operation manuals, he added.
"In communication with our side, they clearly defined their purpose of flight," the source said, adding no additional measures were taken over the matter.
The last such incident took place in early May, when two Russian military aircraft, Tupolev Tu-142s, entered the KADIZ from south of South Korea's southern island of Jeju.
Japan's defense ministry also said on Thursday that two Russian warplanes violated its air defense zone twice earlier in the day.
An air defense identification zone is an area of the skies declared by a state for the early identification and location of foreign planes approaching its territorial airspace to prevent infiltration by foreign planes and accidental clashes. It is not defined in any international law or treaty. (Yonhap)