The commander of US forces in the Pacific says he is concerned about the scale and intent of China's military build-up. Admiral Timothy Keating was speaking at a meeting of a US Senate military commission on Tuesday.

Keating said that China's military build-up poses a threat to Taiwan and US power in the region. He called on China to explain its rapid military expansion. He also called on Taiwan to raise its capability to defend itself against an attack from China.

Beijing's military expenditure this year is close to US$59 billion, a rise of 18 percent on last year. China's military spending has shown double digit growth year-on-year for most of the past twenty years.

Keating also said however he is "cautiously optimistic" that tension across the Taiwan Strait will ease after this month's presidential election in Taiwan. He said both Taiwanese presidential candidates have adopted a conciliatory position towards relations with China.