Doha: South Korea's Ministry of National Defense lodged a protest with China and Russia over their military planes' unauthorized entry into South Korea's air defense zone.

According to Qatar News Agency, a defense ministry official called in military attaches of the Chinese and Russian embassies in Seoul and lodged "a strong protest" over the unauthorized entry, urging both countries to take measures to prevent a recurrence of such activities.

On Saturday, 10 Chinese and Russian military aircraft briefly entered and left South Korea's air defense identification zone (KADIZ) above the country's eastern and southern waters, Yonhap said.

The Korean ministry stressed that the military will continue to respond proactively to activities related to KADIZ in line with international laws to safeguard the country's airspace.