China has conducted nighttime air exercises near Taiwan, in an unprecedented drill marking the latest rise in military tensions between Beijing and Taipei during the coronavirus crisis.

The incident late on Monday forced the Taiwanese air force to scramble to warn off Chinese J-11 fighter jets and KJ-500 airborne early warning and control aircraft as they flew over waters southwest of the island of 23 million, approaching Taiwan’s Air Defence Identification Zone.

Taiwan has repeatedly protested that China has stepped up its military intimidation tactics while it should be focusing its resources on fighting the Covid-19 pandemic which began in the Chinese city of Wuhan.

In one encounter in early March, a Chinese jet reportedly locked onto to a Taiwanese aircraft, which in combat situations is the precursor to a missile launch.

Beijing claims that Taiwan belongs to China and the ruling Communist party has pledged to annex the island, which operates like any other democratic nation – using force if necessary.

Taiwan’s defence ministry has reassured the public that there is no cause for alarm, stressing that “after our air reconnaissance and patrol aircraft responded appropriately, and broadcast (an order) to drive them away, the Communist aircraft flew away from our Air Defense Identification Zone.”

However, on Tuesday, the Global Times, which is often viewed as a mouthpiece of the Chinese state, confirmed the rare nighttime sortie and doubled down on belligerent rhetoric, indicating Beijing’s longer term strategy.

The drills showed that Chinese forces were fully capable of launching military operations on the island at any time of a day, it reported, citing an unnamed military expert who asked not to be named.

The source added that similar drills were expected to become more frequent, along with “island encirclement” exercises as a warning to Taiwan “secessionists.”

China conducted naval and air force exercises near Taiwan in February that crossed the unofficial middle line of the Taiwan Strait.

The move prompted a rebuke from the US state department that it was “completely inappropriate of China to take such an aggressive act.”