Ms Tsai was re-elected by a landslide last year on a promise to stand up to Beijing. In her speech on Sunday, she said Taiwan was “standing on democracy’s first line of defence”.

She said the island would not “act rashly” but would bolster its defences to “ensure that nobody can force Taiwan to take the path China has laid out for us”.

That path, she said, offered “neither a free and democratic way of life for Taiwan nor sovereignty” for its 23 million people.

China’s military flights into Taiwan’s air defence zone had seriously affected national security and aviation safety, she said, and the situation was “more complex and fluid than at any other point in the past 72 years”.