Japan said on Monday, 26 December, that China was trying to expand military capability as Beijing's aircraft carrier has been spotted in Western Pacific. It also said Tokyo was closely monitoring the development, which China calls as a routine exercise.
The country's Chief Cabinet Secretary Yoshihide Suga said that Japan would take all necessary steps for surveillance activity in the area.
Meanwhile, Taiwan also claimed that a group of Chinese warships, led by the country's aircraft carrier has passed through waters south of Taiwan and was heading southwest.
Taiwan's defense ministry said the aircraft carrier, The Liaoning, along with five other vessels, has crossed 90 nautical miles south of Taiwan's southernmost point on Monday morning via the Bashi Channel, between Taiwan and the Philippines.
"Staying vigilant and flexible has always been the normal method of maintaining airspace security," ministry spokesman Chen Chung-chi said, adding that the ministry was continuing to "monitor and grasps the situation".
However, China claimed that its ships were carrying out only routine exercises. The development in the Pacific comes amid renewed tension over Taiwan, which Beijing claims as its own.
China cut off communications with Taiwan in June after the ruling Democratic Progressive Party declined to recognise the "one-China" policy.
The issue came under spotlight recently after US President-elect Donald Trump spoke with Taiwan President Tsai Ing-wen on telephone, breaking the diplomatic protocol.
Senior Taiwan opposition Nationalist lawmaker, Johnny Chiang, said the Liaoning exercise was China's signal to the United States that it has broken through the "first island chain", an area that includes Japan's Ryukyu Islands and Taiwan.
The US has also angered China recently after doing naval patrols near islands in the South China Sea that Beijing claims as it own. In response, the country's navy ship seized a US underwater drone. However, Beijing returned the drone later, calling the Unmanned Underwater Vehicle (UUV) a spying object.