China is to begin a series of unprecedented live-fire drills that would effectively blockade the island of Taiwan, just hours after the departure of US House speaker, Nancy Pelosi, whose controversial visit this week has sparked fears of a crisis in the Taiwan strait. Taiwan has characterised the drills, which will last until Sunday afternoon – and will include missile tests and other “military operations” as close as nine miles to Taiwan’s coastline – as a violation of international law. Ahead of the drill, it said 27 Chinese warplanes had entered its air defence zone. Pelosi arrived in Taipei on Tuesday night under intense global scrutiny, and was met by the foreign minister Joseph Wu and the US representative in Taiwan, Sandra Oudkirk. She addressed Taiwan’s parliament on Wednesday before having public and private meetings with the president, Tsai Ing-wen. “Our delegation came to Taiwan to make unequivocally clear we will not abandon Taiwan, and we are proud of our enduring friendship,” Pelosi said on Wednesday, when she was given Taiwan’s highest civilian order by Tsai. She said US solidarity with Taiwan was “crucial” in facing an increasingly authoritarian China. In a later statement, she said China could not prevent world leaders from travelling to Taiwan “to pay respect to its flourishing democracy”. As Pelosi’s plane took off from Songshan airport on Wednesday evening, Wu waved goodbye from the tarmac. But as the American left, Taiwan was facing days of military activity which threaten to escalate into a fourth Taiwan strait crisis. Taiwan’s defence ministry accused Beijing of planning to violate the international convention on the law of sea, by breaching Taiwan’s sovereign territory. While China’s military often holds live-fire exercises in the strait and surrounding seas, those planned for this week encircle Taiwan’s main island and target areas within its territorial sea. Veerle Nouwens, a senior research fellow at the Royal United Services Institute, a London-based thinktank, said the location of the six exclusion zones was noteworthy. “In particular, the exclusion zones appear to no longer be focused on China’s coastline, but rather encircle Taiwan,” she said, adding that China has a different interpretation as to which laws apply to what it considers its own maritime zones. Taiwanese authorities have said the proximity to some major ports combined with orders for all aircraft and sea vessels to steer clear of the area amount to a blockade. China on Wednesday also expanded its trade suspensions on Taiwan to include additional agriculture products, following a ban on imports earlier in the week from more than 100 Taiwanese food companies. China is Taiwan’s largest trading partner. Taipei has remained defiant in its rhetoric. Tsai said on Wednesday that Taiwan “will not back down” in the face of heightened military threats, and would “do whatever it takes to maintain Taiwan’s peace and stability”. Beijing said its drills were “necessary and just”. Advertisement Beijing’s latest drills are being closely followed by Taiwan, the US and other regional powers, said Nouwens. “The US will be looking for the PLA’s [People’s Liberation Army’s] use of conventional missiles in their inventory – eg, will China conduct anti-ship ballistic missile tests or use air-launched and ship-launched variants of ASBMs? “They will also be paying attention to the types of exercises – eg, whether, how often and how far the PLA cross over the median line, which they did today … crossing well over the median line. “Finally, they’ll also be seeking to get a better sense of the PLA’s coordination between air and maritime forces, particularly given the various scenarios that they’ve highlighted they will be exercising for.” Across the region, there is a growing sense of uncertainty, with the exercises having also upset regional neighbours. Japanese analysts said the northern drills were also a clear warning to their government about islands over which Tokyo and Beijing both claim ownership. “Those plans show that the Sakishima Islands, including Yonaguni, Ishigaki, and Miyako, could be affected by People’s Liberation Army operations as they assume the PLA is operating to the east of Taiwan,” Tetsuo Kotani, a professor of global studies at Meikai University, told the Japan Times. China’s ruling Communist party government, which regards Taiwan as its territory despite it having never ruled the island, has repeatedly warned of retaliation for the visit. On Tuesday night, China’s vice-foreign minister, Xie Feng, “urgently summoned” the US ambassador, Nicholas Burns, to lodge stern representations. China’s ambassador to the UK, Zheng Zeguang, also warned that “those who play with fire will get burned”. Pelosi’s flight took a non-direct path from Kuala Lumpur, with a detour over Indonesia and the Philippines, avoiding the South China Sea, to fly into Taiwan. There had been concerns that China might send PLA aircraft to intercept or tail her plane into Taiwanese airspace. There are also fears of an escalation in cyberwarfare and disinformation. In 7-Eleven stores across Taiwan on Wednesday, the message “Warmonger Pelosi get out of Taiwan” flashed across in-store TV screens. According to local reports, some customers thought the message was a statement of the views of the 7-Eleven franchise owner. But Uni-president, the parent company, told local media it suspected it had been hacked. Shortly before Pelosi’s arrival, Chinese state media reported that Beijing’s Su-35 fighter jets were flying across the Taiwan strait. Taipei subsequently dismissed the announcement as “fake news”. Pelosi earlier said China was making “a big fuss” about this visit because of her status as speaker of the US House of Representatives. “I don’t know if that’s a reason or an excuse,” she said, adding: “Whatever China will do, they will do in their own good time.”