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.

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.

Lai, who took office in May after winning election in January, is detested by China which calls him a "separatist". Beijing claims democratically governed Taiwan as its own territory, a view Lai and his government reject.