State media reported the live-fire drills in six areas around Taiwan got underway at noon local time (04:00 GMT) and will continue until the same time on August 7.
China began military manoeuvres on Tuesday night following Pelosi’s arrival and later announced a raft of retaliatory economic measures in response to Pelosi’s visit.
Military activity continued on Wednesday, with Taiwan saying the drills violated United Nations rules, invaded its territorial space and amounted to a blockade of its air and sea.
On Thursday, the Ministry of National Defense described China’s military activities as “irrational” and with the “intention of changing the status quo and undermining regional peace and stability”.
Beijing claims Taiwan as its own and has not ruled out the use of force to take control of the island.
On Thursday, the Global Times, a state-run tabloid, framed the drills as a rehearsal for “reunification operation(s)”.
“In the event of a future military conflict, it is likely that the operational plans currently being rehearsed will be directly translated into combat operations,” it quoted Chinese mainland military expert Song Zhongping as saying.
It reported the military planned to launch live long-range artillery across the Taiwan Strait.
Taiwan on alert
Some of the six areas where Beijing has indicated the exercises are being held fall within Taiwan’s territorial waters.
The defence ministry said the island’s armed forces remained in a state of alert and were closely monitoring the PLA’s activities.
Taiwan will “uphold the principle of preparing for war without seeking war, and with an attitude of ‘not escalating conflict and not causing disputes’,” the ministry said in its statement.
Earlier it revealed suspected Chinese drones had flown above the Kinmen Islands, Taiwanese territory off China’s southeastern coast, and it had fired flares to drive them away.
Major General Chang Zone-sung of the military’s Kinmen Defense Command told the Reuters news agency that the Chinese drones came in a pair and flew into the Kinmen area twice on Wednesday night, at about 9pm (13:00 GMT) and 10pm (14:00 GMT).
“We immediately fired flares to issue warnings and to drive them away. After that, they turned around. They came into our restricted area and that’s why we dispersed them,” he said.
“There is no justification to use a visit as a pretext for aggressive military activity in the Taiwan Strait,” a statement from the G7’s foreign ministers’ said. “It is normal and routine for legislators from our countries to travel internationally. The PRC’s escalatory response risks increasing tensions and destabilizing the region.”
Foreign ministers from the Association of Southeast Asian Nations (ASEAN), who are meeting in Phnom Penh, also expressed their concern that the rising tension around Taiwan could lead to “miscalculation” and called for “maximum restraint”.
Pelosi’s visit was the first by a sitting speaker of the house, the third most senior politician in the US, in 25 years. Beijing had threatened “serious consequences” if she went ahead with the visit.
The last big crisis in the Taiwan Strait took place in 1996, in the run-up to the re-election of President Lee Teng-hui, who had visited the US the previous year.
China has modernised and expanded its armed forces since then, launching its first aircraft carrier and testing hypersonic weaponry.