Beijing has stepped up pressure on Taiwan and relations have become increasingly frosty since Tsai took office in May last year, as she refuses to acknowledge Taiwan is part of "one China".
China views self-ruling Taiwan as part of its territory, to be reunified at some point.
Tsai warned that China's frequent air and naval drills showed that "its intentions for military expansion in the region are getting more and more obvious".
According to Taiwan's defence ministry, Chinese warplanes conducted 25 drills around Taiwan between August 2016 and mid-December this year.
The latest known drill took place on December 20 when several Chinese planes, including fighters and bombers, passed through the Bashi Channel south of Taiwan to the Pacific and back.
Earlier this year, China sent its only aircraft carrier, the Liaoning, through the Taiwan Strait during a drill as a show of strength, but it did not enter Taiwanese waters.
https://www.msn.com/en-us/news/world...tary-expansion