China and Russia conducted a joint patrol of nuclear-capable bombers over the Sea of Japan on Friday, Nov. 29, their ninth such operation since 2019. The patrol featured China’s H-6N bomber, its first deployment in such an exercise, and Russia’s Tu-95MS strategic bomber, according to Chinese state media.

South Korea’s military reported that 11 Chinese and Russian aircraft entered its air defense identification zone (ADIZ), prompting it to scramble fighter jets. The planes remained in the zone for about four hours but did not breach South Korean airspace. Officials said they lodged formal protests with both Beijing and Moscow over the unannounced flights.

The South Korean military stated that Russian aircraft approached from the northeast over the East Sea, while Chinese planes entered from the south and moved northward. The two groups of bombers met south of Dokdo, a group of islands claimed by both South Korea and Japan, before leaving the ADIZ.

China’s state broadcaster described the patrol as part of an annual plan aimed at strengthening joint training and operational capabilities. Russia has not commented on the exercise.

The joint patrol follows similar missions earlier this year, including a July operation near Alaska that prompted the United States and Canada to dispatch fighter jets. It also comes amid escalating military tensions, including Russia’s recent deployment of a hypersonic missile in Ukraine.

Air defense identification zones, such as South Korea’s ADIZ, require foreign aircraft to identify themselves for security purposes but do not constitute sovereign airspace. These zones often overlap, leading to disputes between nations.

Moscow argued that South Korea’s ADIZ was established unilaterally and does not legally bind other countries. South Korea maintains that all aircraft entering the zone should provide notice and routinely scrambles fighter jets in response to unauthorized entries.