Taiwanese President Tsai Ing-wen pledged on Thursday to work with countries in Southeast Asia and the Western Pacific to ensure sustainable prosperity in the region amid China's military expansion.

Tsai said at an international forum in Taipei that her government will proactively contribute to the creation of a region that is "open, free, inclusive, transparent and equal, and operates under a rules-based order."

"We oppose any heavy-handed and unilateral aggression actions that jeopardize regional security and solidarity," Tsai said via video. "Any political attempt to prevent Taiwan from sharing its experience and making contributions does not serve the collective interests of the region."