A South Korean air force F-15K Slam Eagle takes off from Gwangju Air Base, South Korea, April 19, 2023. (Tyler Harmon/U.S. Air Force)

CAMP HUMPHREYS, South Korea — Six Chinese and Russian military aircraft entered South Korea’s air identification zone Thursday, prompting Seoul to deploy fighter jets in response, according to the Ministry of National Defense.

The aircraft — two from China and four from Russia — were detected prior to entering South Korea’s zone in the Sea of Japan, or East Sea, between 11:53 a.m. and 12:10 p.m., the ministry said in a text message to reporters.

The identification zone is a buffer designated by some countries between international and national airspace in which approaching aircraft are expected to identify themselves.

The six aircraft did not violate South Korea’s airspace; however, the nation’s air force deployed fighter jets “to take tactical measures,” the ministry said.

No additional details on the aircraft were provided by the ministry.

The incident comes six months after four Chinese and four Russian aircraft crossed into South Korea’s identification zone to the south and east of the Korean Peninsula on June 6. South Korean jets responded.

The same day, two Chinese H-6s and two Russian Tu-95 bombers conducted a joint air drill near Japan, prompting Tokyo to scramble fighter jets, according to Kyodo News.