Taiwan's President Tsai Ing-wen accused China of "seriously challenging" peace and stability, describing the island she leads as being on the frontline of tensions in the Pacific.
It comes as Beijing pursues a multi-pronged attack on any claims to sovereignty by self-ruled democratic Taiwan, which it sees as part of its territory to be reunified, by force if necessary.
Relations between Beijing and Taipei have deteriorated since Tsai took office two years ago, as she refuses to acknowledge that Taiwan is part of "one China".
"As Taiwan is on the frontline of the Western Pacific, we are naturally subject to tremendous pressure," Tsai said in a televised speech to mark Taiwan's National Day.
"China's unilateral diplomatic offensive and military coercion have not only harmed cross-strait relations. They have also seriously challenged the status quo of peace and stability in the Taiwan Strait," she added.