Chinese jets conducted drills near Taiwan's airspace on Wednesday for the sixth time this month, as relations between the two rivals worsen.

China sees self-governed Taiwan as part of its territory to be reunified at some point -- by military force, if necessary.

The two sides split after a civil war in 1949. Although Taiwan is a self-ruling democracy, it has never formally declared independence.

The latest drills come just days after China's warplanes flew over the Sea of Japan (East Sea), prompting South Korea and Japan to scramble jets.

Taiwan's defence ministry announced Wednesday that Beijing had directed several planes including jet fighters through the Bashi Channel south of the island, to the Pacific and back.

"China's long-distance (drills) have become more frequent," it said, but urged Taiwanese people not to worry.

It added that it would dispatch its own aircraft and ships to monitor drills "according to protocol".

Relations between Taipei and Beijing have rapidly deteriorated since the inauguration last year of Taiwanese President Tsai Ing-wen, who refuses to acknowledge both sides are part of "one China".

Beijing has cut all official communication with Taipei and stepped up pressure on Tsai's government, including staging a series of naval and air drills near Taiwan since last year.

Local media reports estimate Chinese warplanes have conducted drills around Taiwan at least 20 times this year, compared with a total of eight times last year.

A spokesman for China's air force said last week that bombers and reconnaissance planes had been deployed near Taiwan for "island encirclement patrols" on December 11 in routine training drills.

These exercises aimed to "increase the capacity to safeguard the national sovereignty and the territorial integrity", said Shen Jinke.

In August a Chinese military aircraft entered Taiwan's air defence identification zone (ADIZ) during a drill, prompting Taiwan to urge restraint.

The ADIZ stretches beyond Taiwan's airspace and is used to give early warning of possible incursions.

Five Chinese warplanes entered South Korea's ADIZ during Monday's drill, according to Seoul's Joint Chiefs of Staff.

China's air force said it was the first time its aircraft had flown through the Tsushima Strait between South Korea and Japan.

Source: AFP