Taipei: Four Chinese military aircraft entered Taiwan's air defence identification zone (ADIZ) on Friday, local media reported.

The aircraft was identified as a Shenyang J-11 fighter jet, a Shaanxi Y-8 EW electronic warfare plane, and in a rare appearance near Taiwan, a CAIC WZ-10 attack helicopter and a Russian-made Mi-17 cargo helicopter, Taiwan News reported.

The aircraft appeared in the southwest sector of Taiwan's ADIZ and were warned to leave the area. The Ministry of National Defence said it deployed air defence missile systems to monitor the activities of the aircraft.

Friday's actions marked the seventh day in April that China sent planes into the ADIZ.

The intrusions have been widely described as attempts by China to wear down Taiwan's air defence forces, Taiwan News reported.

An ADIZ is an area that extends beyond a country's airspace where air traffic controllers ask incoming aircraft to identify themselves, according to Taiwan News.

Beijing claims full sovereignty over Taiwan, a democracy of almost 24 million people located off the south-eastern coast of mainland China, despite the fact that the two sides have been governed separately for more than seven decades.

Taipei, on the other hand, has countered the Chinese aggression by increasing strategic ties with democracies including the US, which has been repeatedly opposed by Beijing. China has threatened that "Taiwan's independence" means war.