Taiwan has held live-fire missile tests, as Chinese President Hu Jintao travels to the US for a state visit.
Five out of 19 missiles failed to hit their targets, at the drill attended by President Ma Ying-jeou.
Officials said the drills sent a message to the US that Taiwan still needs American help to defend itself, despite improving ties with China.
Analysts say Taiwan is worried about a potential threat from Beijing after China unveiled a prototype stealth jet.
China continues to claim the island as part of its territory, and has not renounced the use of force to achieve reunification.
Taiwan, a democracy, has been ruled separately since the end of a civil war in 1949.
The Taiwanese military said the exercises were routine, and aimed at boosting its defence capabilities.
Speaking to the BBC, Taiwan's Deputy Defence Secretary Andrew Yang said the operation was not offensive in nature, but was intended to stop any attacks by China.
"China still holds the option to use force against Taiwan. They have never renounced the use of force. We consider this a direct threat against us, so we need to consolidate our armed forces."
Advanced weapons
Mr Yang told the BBC the drills were also designed to send the US a clear message - that Taiwan still needs US help in defending itself, even as it builds closer economic ties with Beijing.
He said that Taiwan was developing its own advanced missiles, which would be able to reach military bases and airports on China's east coast.
However, the island depends on the US for advanced weapons.
The BBC's Cindy Sui in Taipei says Taiwan is still hoping to purchase advanced fighter jets and submarines, to upgrade its ageing fleet and narrow the gap with China.
Washington, however, needs Beijing's help on a host of issues - from North Korea to currency appreciation, our correspondent says.
The last time the US approved an arms package to Taiwan 12 months ago, China was furious, cancelling military exchanges and security talks.
