South Korea's defense ministry said Saturday it summoned a Russian military envoy over Russian planes' violation of the country's air defense identification zone (KADIZ), Yonhap reported.

The Ministry of Defense said Park Chul-kyun, deputy director-general for international policy of the ministry, summoned Andrey Falileev, Russia's military attache to South Korea, to protest Russian military planes' unauthorized entry into the KADIZ on Friday.

"Russian military planes' KADIZ entry will not help efforts to stabilize the Korean Peninsula as well as Northeast Asia," Park told Falileev, according to the ministry. "Since there is also a possibility of mid-air collision, we request Russia to recognize the seriousness of this issue and look for measures to prevent such incidents from happening again."

Meanwhile, the Ministry of Foreign Affairs said its director-general for European Affairs Jung Ki-hong summoned Maxim Volkov, the No. 2 diplomat at the Russian Embassy to South Korea, and expressed regret over the KADIZ violation.