In a separate incident, a Chinese military plane today crossed an unofficial airspace boundary in the Taiwan Strait after a missile-intercept drill the day before – prompting the island to scramble fighter jets. China considers Taiwan to be part of its territory, and the question of sovereignty is widely regarded by the international community as a major potential flashpoint.
The US C-40A, which is a military version of the Boeing 737, entered Taiwan air space with permission, though it did not land at any Taiwan airports, Taiwan’s Defence Ministry confirmed on Tuesday.
China’s Taiwan Affairs Office said the US aircraft had “harmed our sovereignty, security and development rights, and contravened international law and the basic norms of international relations”.
The statement, carried by state media, added: “It was an illegal act and a seriously provocative incident.
“We express strong dissatisfaction and resolute opposition.”
Foreign Ministry spokesman Hua Chunying later said Beijing “firmly opposes and strongly condemns this move by the US”, claiming the flight “gravely violates international law and basic norms governing international relations.”
She added: “We urge the US to adhere to the one-China principle and the three China-US joint communiques, and immediately stop such unlawful and provocative behaviours.
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“There were no interactions or intercepts from any aircraft during the flight.”
Taiwan is entirely separately governed from China and controls its own air space.
On the same day as the US aircraft flew over the island, Taiwan’s air force had to warn off several Chinese fighter jets which briefly entered Taiwan’s air defence identification zone.
Taiwan has repeatedly complained about Chinese drills near the island.
The United States has stepped up its military activities near the island too, with semi-regular US Navy voyages through the narrow strait which separates the island from China.
While Washington and Taipei have no formal diplomatic ties, the United States is Taiwan’s strongest international supporter and main arms supplier.
Taiwan’s National Chung-Shan Institute of Science and Technology test-fired two missiles off the eastern county of Taitung and the Jiupeng military base in the southernmost county of Pingtung on Thursday night – although there was no confirmation this was what caused the US plane to be rerouted.
As a result, a PLA Yun-8 transport plane crossed the median line in the strait on Friday.
A statement issued by Taiwan’s defence ministry said: “We detected the Chinese Communist Yun-8 aircraft flying southwest into Taiwan this morning and immediately dispatched our fighter jets to shadow it and disperse through radio warning.”
Other missiles will be tested in coming days, the Taiwan Fisheries Agency has confirmed.
Two months ago, Taiwan test-fired a Tien Kung-3 and a medium-range Yun Feng (Cloud Peak) land-attack cruise missile sometime between April 5 and April 23 at the Jiupeng base.
The Tien Kung can intercept incoming missiles – but the Yun Feng, with a range of 1,500km, can strike targets in inner China, including Beijing.