North Korea's foreign minister has said his country is ready to halt its nuclear tests if the United States suspends its annual military exercises with Seoul.

North Korea has said its military is ready to pre-emptively attack and "liberate" Seoul, in its latest outburst against the joint military drills by the United States and South Korea.

Taiwan has held military drills on an island it controls just off the Chinese coast, in a renewed signal of its determination to defend itself from Chinese threats.