SEOUL – The South Korean Ministry of National Defense issued a stern protest on June 28, 2026, following the unauthorized entry of more than 10 Chinese and Russian military aircraft into the Korea Air Defense Identification Zone (KADIZ) the previous day.

Incursion into the KADIZ

According to the Joint Chiefs of Staff (JCS), the group of bombers and fighters from China and Russia sequentially entered and exited the KADIZ over the East Sea and the South Sea on the morning of June 27. The South Korean military had detected the aircraft before they crossed into the zone and deployed Air Force fighter jets to conduct tactical maneuvers and prepare for any potential contingencies.

While the military confirmed that none of the foreign aircraft violated South Korea’s sovereign airspace, the lack of prior notification was a significant point of contention. An Air Defense Identification Zone (ADIZ) is an arbitrary buffer zone established to identify and monitor approaching military aircraft for security purposes; while it is not recognized as sovereign airspace under international law, it is standard international practice for military aircraft to submit flight plans and provide notifications before entry.

The Ministry of National Defense confirmed that the International Policy Officer held meetings with the Chinese and Russian defense attaches in Seoul on June 28 to register a "grave protest" and urge both nations to prevent future occurrences. Chinese defense officials later stated that their air forces were conducting a "strategic air patrol" to demonstrate their capability to uphold regional peace, though they did not explicitly mention the KADIZ.

High-Level Defense Diplomacy Amid Tensions

The incident occurred as South Korea is actively seeking to stabilize its regional security environment. On the same weekend, South Korean Defense Minister Ahn Gyu-back hosted Japanese Defense Minister Shinjiro Koizumi in Seoul for a bilateral summit—the first visit by a Japanese defense chief to South Korea for independent talks in 11 years.

During their meeting, the two ministers agreed to bolster defense cooperation in several key areas:

Aerobatic Team Cooperation: The two sides committed to continued exchanges between the South Korean "Black Eagles" and Japan’s "Blue Impulse" teams, building on a recent refueling support exchange in Okinawa.
Maritime Safety: The ministers agreed to advance search and rescue training for various maritime accident scenarios.
Advanced Technology: The two nations will initiate discussions on collaborative efforts in high-tech fields, including Artificial Intelligence (AI) for defense applications.
Despite the warming ties, sensitive issues such as the Acquisition and Cross-Servicing Agreement (ACSA)—a deal that would facilitate the mutual supply of fuel and ammunition—were not included in the official agenda, reflecting the complex historical and political sentiments still present in the bilateral relationship.

The meeting concluded with a reaffirmation of the commitment to the complete denuclearization of the Korean Peninsula and a pledge to maintain trilateral security cooperation involving the United States to address the increasingly challenging regional security environment.