Taiwanese President Tsai Ing-wen has stressed that Taiwan will not bow to pressure from China, which has made clear it will not renounce the use of force to achieve reunification.

Tsai was speaking on Tuesday at the opening ceremony of the World Movement for Democracy's three-day global assembly in Taipei.

The movement is co-sponsored by the US nongovernmental organization the National Endowment for Democracy.

Taiwanese authorities say more than 200 pro-democracy activists from about 70 countries and regions are taking part in the session.

Tsai criticized China for its increasingly aggressive attempts to threaten Taiwan's democracy, citing military intimidation, cyberattacks and economic coercion.

She said that even under constant threat the people of Taiwan refuse to shy away from challenges and continue to combat authoritarian forces looking to undermine their democratic way of life.

Tsai's remarks come in response to a refusal by Chinese President Xi Jinping to renounce the use of force against Taiwan, as he began his third term as head of China's ruling Communist Party.