Taiwan's Defence Ministry has said that it had spotted 19 J-10 Chinese fighter planes in its air defence zone in the past 24 hours.
Taiwan's forces monitored the situation, including sending up its own air force planes.
Meanwhile, China has said its activities in the area are justified as it seeks to defend its
territorial integrity and to warn the United States against "colluding" with Taiwan, despite the anger this causes in Taipei.
The Taiwanese government has repeatedly offered talks with China but says the island will defend itself if attacked and that only the Taiwanese people can decide their own future.