Taiwan on Sunday reported the largest incursion since October by China's air force in its air defence zone, with the island's defence ministry saying Taiwanese fighters scrambled to warn away 39 aircraft in the latest uptick in tensions.

Taiwan, which China claims as its own territory, has complained for more than a year of repeated missions by China's air force near the democratically governed island, often in the southwestern part of its air defence identification zone, or ADIZ, close to the Taiwan-controlled Pratas Islands.

Taiwan calls China's...