South Korea’s military said Friday it grounded fighter jets as five Chinese and six Russian military aircraft flew through its air defense zone, an area larger than the country’s airspace.

Five Chinese and six Russian military aircraft entered and exited the Korean air defense identification zone in the East and Southern Seas from 9:35 a.m. (0035 GMT) to 1:53 p.m., the Seoul chiefs of staff said in a statement.

But the planes entered KADIZ “without violating South Korean airspace,” the JCS said, adding that the military “identified the planes before they entered KADIZ and used Air Force fighter jets to conduct tactical preparations.” to take action on any eventuality.”

An air defense identification zone is an area larger than a country’s airspace in which it attempts to control aircraft for security reasons. However, the concept is not defined in any international treaty.

China’s defense ministry described the flights as “their ninth joint strategic patrol” that took place over the Sea of ​​Japan, also known in South Korea as the East Sea.

In a post on its official social media account, the company added that Friday’s flights took place “in accordance with the annual cooperation plan between the two.” Chinese and Russian militaries.”

South Korean military officials told local media that Chinese military aircraft headed toward the small Dokdo Islands off South Korea’s east coast after flying between the Korean peninsula and Japan near the disputed submerged rock of Ieodo.

Russian planes also flew south toward the Dokdo Islands, called Takeshima in Japanese.

Officials said the Chinese and Russian planes flew together over the sea south of Dokdo before departure.

Since 2019, China and Russia have regularly flown military aircraft into the South Korean air defense zone without prior notice, citing joint exercises.

Similar incidents occurred in June and December last year and in May and November 2022, with Beijing and Moscow describing the flights as “joint strategic air patrols.”

South Korea’s Defense Ministry on Friday “expressed regret” to China and Russia that their military aircraft had entered the South’s air defense zone and “flyed for a long period of time without prior notice,” it said in a statement.

The ministry called for “appropriate measures to be taken to prevent a recurrence,” adding that such measures “could unnecessarily increase tensions in the region.”

China and Russia have expanded their military and defense ties since Moscow’s order troops to Ukraine almost three years ago.

Both are also traditional allies of North Korea, Seoul’s archenemy.

South Korea and the USA have accused North Korea of ​​sending nuclear weapons Thousands of soldiers to Russia to fight in Ukraine, and this month Pyongyang ratified a landmark defense pact with Moscow.

The South Korean fighter jet crash is the latest incident between Russian and Chinese militaries in recent months.

Italy and Norway responded by mobilizing jets earlier this month Russian planes were spotted over the Baltic Sea and along the Norwegian coast.

In September, Japan said so Fighter planes used flares to warn a Russian reconnaissance plane to leave northern Japanese airspace.

That same month, the U.S. military moved about 130 soldiers along with mobile rocket launchers to a remote island in the Aleutian chain of western Alaska, amid a recent increase in Russian military aircraft and ships approaching American territory. Eight Russian military aircraft and four naval ships, including two submarineshave come close to Alaska in recent days as Russia and China conducted joint military exercises.

In July, two Russian Tu-95s and two Chinese H-6s entered the Alaska Air Defense Identification Zone. NORAD said. The bombers were intercepted by U.S. F-16 and F-35 fighter jets as well as Canadian CF-18s and other support aircraft, a U.S. defense official confirmed to CBS News.