Taiwan's defense ministry said on Saturday morning that over the past 24 hours it had detected 20 Chinese air force planes entering the island's air defense zone, including a combat drone the flew along Taiwan's Pacific east coast.

Democratically governed Taiwan, which China claims as its own territory, has complained for three years of increased military pressure from Beijing.

Last Saturday, China held a day of drills around Taiwan in an angry response to brief stopovers this month in the United States by Vice President William Lai.

Offering further details on Friday's Chinese activity, Taiwan's defense ministry said the aircraft involved included of Su-30 and J-10 fighters and anti-submarine aircraft.

China's defense ministry did not answer calls seeking comment on Saturday.

Some of the fighters and drones crossed the median line of the Taiwan Strait, previously an unofficial barrier between the two sides but which over the past year Chinese aircraft have routinely crossed, according to a map Taiwan's ministry provided.

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A TB-001 drone flew to Taiwan's north, headed into the Pacific, broadly tracking the island's east coast, then looped back along the same flight path and returned to China, the map showed.

Chinese state media has called the TB-001 the "twin-tailed scorpion" and shown pictures of it with missiles under its wings, saying it is capable of high altitude, long-range missions.

In April, Taiwan said the same model of drone had flown around Taiwan.

The ministry this week said it could not judge whether the drills China started last Saturday had formally ended, as Beijing had made no announcement. China has continued military movements around Taiwan.

This week China condemned the United States for approving further arms sales to Taiwan, and the island announced it planned to spend $3 billion next year to buy weapons including fighter jets.

Taiwan has not reported any Chinese military aircraft in its territorial air space, though it has said planes have come close to island's contiguous zone, which is within 24 nautical miles or 44 kilometers off its coast.

Japan's defense ministry said Friday it scrambled jet fighters to monitor Chinese air force bombers and drones flying near the country's southwestern Okinawa Island and Taiwan.