CNN's Aditya Raj Kaul tweeted: "Taiwan's Defence Ministry says that 8 Chinese PLA Bombers and 4 Fighters have Breached Island's Air Defence Zone. Airborne alert sorties had been tasked, radio warnings issued and air defense missile systems deployed to monitor the activity."

Taiwan's air force deployed missiles to "monitor" the incursion, the island's Defence Ministry said.

China has conducted almost daily flights over the waters between the southern part of Taiwan, led by President Tsai-ing wen, and the Taiwan-controlled Pratas Islands in the South China Sea in recent months.

However they have generally consisted of just one or two reconnaissance aircraft.

The presence of so many Chinese combat aircraft on this mission - Taiwan said it was made up of eight nuclear-capable H-6K bombers and four J-16 fighter jets - is unusual.

A map provided by Taiwan's Defence Ministry showed that the Chinese aircraft, which also included a Y-8 anti-submarine aircraft, flew over the same waters where the most recent Chinese missions have been taking place near the Pratas Islands, though still well away from mainland Taiwan.

Taiwan's air force warned away the Chinese aircraft and deployed missiles to monitor them, the ministry added, using standard wording for how it responds to such activities.

In a statement the Defence Ministry said: "Airborne alert sorties had been tasked, radio warnings issued and air defence missile systems deployed to monitor the activity."

There was no immediate comment from China.