TAIPEI (Reuters) -- Taiwan's Defense Ministry said it spotted 28 Chinese air force planes in its air defense zone on Wednesday morning, part of what Taipei calls regular harassment by Beijing amid heightened tensions across the Taiwan Strait.
Democratically governed Taiwan, which China views as its own territory, has complained in recent years of stepped-up Chinese military activities near the island as Beijing seeks to assert its sovereignty claims.
Taiwan's Defense Ministry said that beginning around 6 a.m. (2200 GMT Tuesday), Chinese warplanes including J-10 fighters had flown into the southwestern corner of the island's air defense identification zone, or ADIZ.
Some of the Chinese aircraft crossed the Bashi Channel to carry out drills with the Chinese aircraft carrier Shandong in the Pacific, the ministry added.
China's Defense Ministry did not immediately respond to a request for comment.
Taiwan's forces monitored the situation, including sending up their own air force planes and activating air defense systems, the island's ministry added, using the normal phrasing for its response to such Chinese incursions.
A Chinese naval formation led by the Shandong entered the western Pacific for training, Taiwan's Defense Ministry said on Monday.
Japan's Defense Ministry later said its Maritime Self-Defense Force had spotted the Shandong and five accompanying Chinese navy vessels, including two frigates and two missile destroyers, around 650 kilometers south off Japan's southwestern Miyako island on Wednesday morning.
Japan sent a destroyer to monitor the Chinese ships and confirmed that jet fighters and helicopters aboard the Shandong conducted landing training, the ministry added.
Separately, more than 20 Chinese warships, including Type 055 destroyers, sailed through the Bashi Channel and Miyako Strait into the Pacific on Wednesday, a senior official familiar with security planning in the region told Reuters.
The Chinese naval maneuver, along with the training exercises by the carrier group, were an "obvious challenge" to the recent military activities by the United States and its allies in the region, the person said.
"They want to show that they got the total control of the west of the first island chain," the person said, referring to the area that runs from Japan through Taiwan, the Philippines and on to Borneo, enclosing China's coastal seas.
A U.S. and a Canadian warship sailed through the Taiwan Strait on Saturday, the U.S. Navy said, marking the second such joint mission since June and coinciding with the leaders of both countries attending the Group of 20 summit in India.
The two countries' navies also conducted a series of exercises in the South China Sea this week, according to the U.S. Navy.
China has been increasing its military operations around Taiwan over the past few years in response to what it calls "collusion" between Taiwan independence forces and the U.S.