For the first time, Taiwan's military has confirmed that the People's Liberation Army flew drones over the Taiwan Strait.
Taiwan's defence ministry said 45PLA aircraft flew around Taiwan on Thursday, 25 of which crossed the median line. On Friday and Saturday, more drones crossed the line.
On Monday, it said another PLA drone had entered Taiwan's southwest air defence identification zone.
The Taiwan military shot down a civilian drone that flew into restricted waters near the Chinese mainland.
In 1955, Benjamin Davis Jr., a senior US Air Force commander, demarcated the median line of the Taiwan Strait, which separates mainland China and Taiwan and connects the East and South China seas.
Since Nancy Pelosi paid a visit to Taiwan on August 2 and 3, there has been an increase in tension across the strait. She visited the island and the PLA launched drills around it.
Beijing has never ruled out using force to take control of the island under the one-China policy. The US doesn't recognise Taiwan as an independent state but doesn't want it to be taken by force.
Beijing has been sending drones to the Taiwan Strait since it increased its patrols, according to a source close to the PLA.
The source said that the Taiwanese military wasn't aware of it until recently, but that the PLA used to send drones to perform sensitive tasks in the sky before sending fighter jets.
The PLA's Eastern Theatre Command announced "joint combat-readiness security patrols" around Taiwan in November, according to Lu Li-Shih, a former instructor at Taiwan's Naval Academy.
Lu said that the Taiwanese military should have known about thePLA drones. It has to reveal the details because Tokyo has reported it.
The BZK-005 and the TB-001 were first spotted by Japan's Self- Defence Forces flying over waters off the northeastern coast of Taiwan. The Chinese military has been using the two drones over the East China Sea.
A maximum flight time of 40 hours is possible with the BZK-005.
The twin-tailed scorpion is a combat and spy UAV. It can fly for 35 hours and has a range of 6,000 km.
At the end of July, as Taiwan carried out its annual Han Kuang military exercises, the Japanese spotted a small plane in the Miyako Strait off Okinawa and tracked it to a location off the west coast of Taiwan.
Taiwan's military has begun using its Bee Eye radars to help frontline troops detect drones and spy jets from the mainland.
The China Times reported on Friday that Taiwan plans to spend nearly US$700 million to buy four American drones, but they will take years to deliver.
The Taiwanese military hopes the MQ-9B can help it better watch the seas with a range of up to 6,000 km and 40 hours of flight time.
Zhou Chenming is a researcher from the Yuan Wang military science and technology think tank.