China's Ministry of National Defense on Friday denounced Japanese military aircraft disrupting the routine patrols of Chinese administrative aircraft.

At a press conference, an official with the ministry confirmed that China sent two J-10 fighters to the East China Sea after a Y-8 aircraft was closely followed by two Japanese F-15 fighters as it patrolled the southwest airspace of the East China Sea oil platform on Thursday.

The two J-10 fighters were sent to monitor the Japanese fighter jets tailing the Y-8 as well as another Japanese reconnaissance plane spotted in the same airspace, the official said.

Furthermore, the official said Japanese military aircraft have been increasingly active in closely scouting Chinese aircraft. The activity zone of Japanese military aircraft has also expanded recently, which is the root cause of security disputes concerning territorial waters and airspace between the two countries.

The Chinese military will be on high alert and China will resolutely protect the security of its air defense force and uphold its legitimate rights, the official said.

The official also called for the Japanese side to respect relevant international laws and to prevent security disputes by taking effective measures.