China has no justification for using an annual national day speech by Taiwan as a pretext for military pressure, the United States said on Wednesday, ahead of scheduled remarks by the island's president that Taiwan officials say Beijing is likely to follow with military drills.

President Tsai Ing-wen, in the final National Day address of her second term, reiterated that U.S.-Taiwan relations remained "rock solid."

Taiwan President Lai Ching-te is escalating tensions with "sinister intentions", China's government said, ahead of a keynote speech Lai will give in Taipei that could set off a Chinese military response.