China’s military on Monday dispatched air, navy and rocket troops to conduct joint military drills around the island of Taiwan — a move Beijing called a “stern warning” against separatist and “external interference” forces.

Taiwan said it was placing its forces on alert and called the Chinese government “the biggest destroyer of peace.”

Taiwan’s aviation authority said more than 100,000 international air travellers would be affected by flight cancellations or diversions.

The drills came after Beijing expressed anger at what could be the largest-ever U.S. arms sale to the self-ruled territory and at a statement by Japan’s prime minister, Sanae Takaichi, saying its military could get involved if China were to take action against Taiwan. China says Taiwan must come under its rule.

The Chinese military did not mention the United States and Japan in its statement on Monday.

A ship appears to fire a weapon in this screengrab from a video.A ship fires a weapon during drills east of Taiwan, in this screenshot from a video released by the Eastern Theatre Command of China’s People’s Liberation Army on Monday. (Eastern Theatre Command of China’s People’s Liberation Army/Reuters)

Taiwan’s Defence Ministry said in a post on X that rapid response exercises were underway, with forces on high alert to defend the island. In a separate statement, it said it had deployed appropriate forces in response, conducting combat readiness drills.

“The Chinese Communist Party’s targeted military exercises further confirm its nature as an aggressor and the biggest destroyer of peace,” the ministry said.

Senior Col. Shi Yi, spokesperson of China’s People’s Liberation Army’s Eastern Theatre Command, said the drills would be conducted in the Taiwan Strait and areas to the north, southwest, southeast and east of the island.

Shi said the activities will focus on sea-air combat readiness patrol, “joint seizure of comprehensive superiority” and blockades on key ports. It was also the first large-scale military drill where the command publicly mentioned one of the goals was “all-dimensional deterrence outside the island chain.”

“It is a stern warning against ‘Taiwan independence’ separatist forces and external interference forces, and it is a legitimate and necessary action to safeguard China’s sovereignty and national unity,” Shi said.

China and Taiwan have been governed separately since 1949, when a civil war brought the Communist Party to power in Beijing. Defeated Nationalist Party forces fled to Taiwan. The island has operated since then with its own government, though the mainland’s government claims it as sovereign territory.

Live firing exercises expected

The command on Monday deployed destroyers, frigates, fighters, bombers and unmanned aerial vehicles, alongside long-range rockets, to the north and southwest of the Taiwan Strait. It carried out live fire exercises against targets in the waters as well. Drills to test the capabilities of sea-air co-ordination and precise target hunting were also conducted in the waters and airspace to the east of the strait.

Hsieh Jih-sheng, deputy chief of the general staff for intelligence of the Taiwanese Defence Ministry, said that as of 3 p.m. local time Monday, 89 aircraft and drones were operating around the strait, with 67 of them entering the “response zone” — airspace under the force’s monitoring and response. In the sea, the ministry detected 14 navy ships around the strait and four other warships in the Western Pacific, in addition to 14 coast guard vessels.

“Conducting live-fire exercises around the Taiwan Strait … does not only mean military pressure on us. It may bring more complex impact and challenges to the international community and neighbouring countries,” Hsieh told reporters.

Military drills are set to continue Tuesday. Taiwan’s Civil Aviation Administration said Chinese authorities had issued a notice saying seven temporary dangerous zones would be set up around the strait to carry out rocket-firing exercises from 8 a.m. to 6 p.m. local time on Tuesday, barring aircraft from entering them.

Taiwan building ‘T-dome’ missile shield to counter China’s threat

Taiwan’s President Lai Ching-te announced during the country’s National Day celebrations that it would build an air defence system in the mould of Israel’s Iron Dome to protect against ‘hostile threats’ to the island coming from China.

The Taiwanese aviation authority said more than 850 international flights were initially scheduled during that period and the drills would affect more than 100,000 travellers. More than 80 domestic flights, involving around 6,000 passengers, were also cancelled, it added.

The command released themed posters about the drills online, accompanied by provocative wording. One poster depicted two shields with the Great Wall alongside three military aircraft and two ships. Its social media post said the drills were about the “shield of justice, smashing illusion,” adding that any foreign interlopers or separatists touching the shields would be eliminated.

Last week, Beijing imposed sanctions against 20 U.S. defence-related companies and 10 executives, a week after Washington announced large-scale arms sales to Taiwan valued at more than $10 billion US. If approved by the U.S. Congress, it would be the largest-ever American weapons package to the self-ruled territory.

Under U.S. federal law in place for many years, Washington is obligated to assist Taipei with its defence — a point that has become increasingly contentious with China. The U.S. and Taiwan had formal diplomatic relations until 1979, when President Jimmy Carter’s administration recognized and established relations with Beijing.

Taiwanese army on high alert

Monday’s drills heightened tensions on both sides. Karen Kuo, spokesperson for the Taiwanese president’s office, said the operation was undermining the stability and security of the Taiwan Strait and Indo-Pacific region, and openly challenging international law and order.

“Our country strongly condemns the Chinese authorities for disregarding international norms and using military intimidation to threaten neighbouring countries.” she said.

Taiwan’s Defence Ministry released a video that featured its weapons and forces in a show of resilience. Multiple French Mirage-2000 aircraft conducted landings at an air force base.

Beijing sends warplanes and navy vessels toward the island on a near-daily basis, and in recent years, it has stepped up the scope and scale of these exercises. In October, the Taiwanese government said it would accelerate the building of a “Taiwan Shield” or “T-Dome” air defence system in the face of the military threat from China.

The military tensions came a day after Taipei Mayor Chiang Wan-an said he hoped the Taiwan Strait would be associated with peace and prosperity, instead of “crashing waves and howling winds,” during a trip to Shanghai.