“Our military has sent out alerts, deployed air patrols and naval vessels, and activated land-based missile systems in response to the situation,” the ministry said.
China has not yet made any statements about the purpose of Saturday’s military exercises.
The Chinese Communist Party considers Taiwan its territory, though it has never controlled it, and has long vowed to “reunite” the island with mainland China — by force if necessary.
But the full ramifications of her visit are only now coming to light as China halts cooperation in several areas, deteriorates already tense US-China ties and ramps up exercises in the air and waters around Taiwan.
According to the Taiwan Ministry of Defense, 68 Chinese warplanes were reported in the Taiwan Strait on Friday.
Of those, 49 entered Taiwan’s Air Defense Identification Zone – a buffer of airspace commonly referred to as an ADIZ.
That was just a few planes short of last year’s record when 56 Chinese warplanes entered the ADIZ on the same day.
Nineteen of the warplanes also crossed the median line separating the Taiwan Strait on Friday, the ministry said.
That was the first time China sent missiles over the island.
Also on Thursday, two Chinese drones flew near the Japanese prefecture of Okinawa, prompting the Japanese self-defense force to scramble fighter jets in response.
According to Chinese state media, the exercises will last until Sunday local time in Beijing.
Japan and other G7 economies have urged China to halt its exercises in the strait and maintain the status quo in the region.
Beijing responded by lashing out diplomatically, canceling future phone calls between Chinese and US defense leaders, annual naval meetings between the two countries and scheduled meetings between Chinese and Japanese officials.
China’s foreign ministry on Friday announced a series of countermeasures against the US, including sanctions against Pelosi and her immediate family.
China accuses US of ‘navigation bullying’
China has also suspended bilateral climate talks; cooperation on the repatriation of illegal immigrants, cross-border crime and drug operations; and legal aid in criminal matters.
John Kirby, the communications coordinator at the National Security Council, said not all communications between the US and China had been halted and certain channels between senior leaders remained open, but added that the suspensions were still an “irresponsible act”.