TAIPEI, Taiwan — President Tsai Ing-wen of Taiwan called on Saturday for domestic and international support of the island’s de facto independence, days after China’s leader, Xi Jinping, warned that unification with China was inevitable.

“It is impossible for me or, in my view, any responsible politician in Taiwan to accept President Xi Jinping’s recent remarks without betraying the trust and the will of the people of Taiwan,” Ms. Tsai said in a briefing for foreign reporters in Taipei, Taiwan’s capital.

“We hope the international community will pay attention and combine efforts to speak out on our behalf,” she said.

Mr. Xi’s speech, his first major address on Taiwan, has given Ms. Tsai a chance to position herself as the young democracy’s defender, both to the outside world and to voters who will decide next year whether she stays in office. Her party was battered in local elections in November, but since Mr. Xi’s address there has been a groundswell of support for her on Taiwan social media and even, to some degree, in publications that tend to oppose her.