As the operations in response to a visit by US House Speaker Nancy Pelosi entered their second day, China touted its military exercises around Taiwan as proof of its ability to blockade the self-ruled island in the event of war.

According to Taiwan’s Ministry of National Defense, at least 68 Chinese warplanes and 13 warships conducted maneuvers off the coast of Taiwan on Friday. During the operation, some of China’s military aircraft and ships crossed the Taiwan Strait’s median line, a notional boundary that Taipei claims delineates areas of de facto control, according to the ministry.

The flurry of military sorties flown by Beijing on Friday, which set a record for such activity since Taiwan’s military began disclosing the data in September 2020, came after China encircled Taiwan with rocket and ballistic-missile fire the day before. Chinese military experts and state media have described the four-day exercises as unprecedented. They were a “significant escalation,” according to US Secretary of State Antony Blinken, who was in Cambodia for a regional meeting.

Chinese forces conducted live firing in six delineated zones facing Taiwan’s military bases and major commercial ports, allowing China’s military, the People’s Liberation Army, to form a blockade around the island for the first time, a breakthrough highlighted by Beijing’s state media outlets. The areas overlap with what Taiwan claims as its territorial waters.

According to Maj. Gen. Meng Xiangqing, a professor at the People’s Liberation Army National Defense University, the PLA launched missiles over Taiwan on Thursday, the first time the military has done so. Gen. Meng did not say how many were fired, but he did say they flew over an area where Taiwan has Patriot antimissile batteries and is monitored by the US Navy. Taiwan reported that Beijing launched 11 ballistic missiles near the island.

It was also the first time that Chinese aircraft carriers participated in an exercise in a group formation, according to Gen. Meng. Earlier this week, two of China’s carriers, the Liaoning and the Shandong, were training together ahead of Mrs. Pelosi’s arrival in Taiwan, which coincided with the PLA’s 95th anniversary. The carriers’ whereabouts could not be determined.

On Thursday afternoon, the PLA’s Eastern Theater Command announced that all live-fire operations in the waters east of Taiwan had been completed successfully, lifting traffic controls in the area. It said late Friday that the second day of drills went off without a hitch.

Over 200 vessels that frequently navigate the waters around Taiwan have left the six zones. According to Lloyd’s List Intelligence data, only a few ships were still sailing in those zones on Friday, down from an average of 240 per day over the previous week. The Taiwan Strait is a major shipping route, with approximately half of the world’s container fleet and 90% of the world’s largest ships by tonnage passing through it last year.

Taiwan’s two largest ports, Kaohsiung and Keelung, are still open for business, but ship arrivals have dropped by a quarter in the last two days, according to data.

While the general mood in Taiwan remained calm following the conclusion of Thursday’s exercises, Taiwanese President Tsai Ing-wen urged Beijing to exercise restraint. On Friday, a prominent figure in Taiwan’s world-leading semiconductor industry announced a $100 million donation to promote civil defense and counter China’s psychological warfare.

According to Robert Tsao, founder of United Microelectronics Corp., or UMC, there are people in Taiwan who will not be swayed by Beijing’s economic might or intimidated by its military might. He urged more people to join the defense of the island.

UMC, a Taiwanese chipmaker with two manufacturing plants in China, referred a request for comment to Mr. Tsao without elaborating further. After his retirement, Mr. Tsao remains honorary chairman of UMC but is no longer involved in the company’s day-to-day operations. On Friday afternoon, China said that it was suspending climate-change talks with the U.S. and scrapping some military exchanges in response to Mrs. Pelosi’s visit. The countermeasures include the cancellation of calls between military leaders and two security meetings, and the suspension of cooperation in fighting crime. It also announced sanctions against Mrs. Pelosi and her immediate family.