Self-ruled Taiwan scrambled fighter jets after China's aircraft carrier Liaoning passed through the strait of Taiwan en route to Hong Kong, where it will berth as part of events to mark the 20th anniversary of the handover of the territory.
Hong Kong was back to business as usual on Sunday after the main handover anniversary celebrations, which included a dramatic fireworks display and Xi Jinping’s first visit to the territory as Chinese president.
During his trip, Mr Xi visited the People’s Liberation Army (PLA) barracks, and in a tough speech warned Hong Kong’s democratic activists not to cross a “red line” by challenging Beijing’s authority in the territory.
The Soviet-built Liaoning is due to arrive in Hong Kong on Friday, where it will be open to the public in a bid to showcase China’s growing naval might.
PLA spokesperson Liang Yang said a flotilla including Liaoning would visit Hong Kong. The formation would also include guided-missile destroyers, missile frigates, J-15 fighter jets, and helicopters.
“The visit will help increase Hong Kong residents’ understanding of achievements made in national defence and army-building, especially naval-building,” Mr Liang said, quoted by the Xinhua news agency.
There is also speculation that China’s new J-20 stealth fighter jet could fly over Hong Kong as part of the anniversary celebrations.
China's territorial ambitions in the South China Sea have angered its regional neighbours.
Taiwanese jets and ships were deployed to shadow Liaoning’s passage through the Taiwan Strait, Taiwan’s defence ministry said in a statement, according to Reuters.
The ministry said the Chinese aircraft carrier entered Taiwan’s air defence identification zone on Saturday and sailed west of the middle of the strait.
It is the third time that the aircraft carrier has sailed close to Taiwan, the ministry said. Nothing abnormal was detected.
Civil war
Defeated nationalist Kuomintang (KMT) forces fled to Taiwan in 1949 after losing the Chinese civil war to the Communists.
Beijing has never renounced the possible use of force to annex Taiwan and bring it under its control, and considers Taiwan to be an errant province.
Last week, the US state department approved the sale of more than $1 billion (€894 million) in arms to Taiwan, in a move that angered Beijing.
Taiwan has been closely watching the handover anniversary events, while the island has become a top destination for Hong Kongers seeking to emigrate.
The strong focus on military matters during Mr Xi's three-day visit to Hong Kong and his tough talk on quelling moves to democracy are seen as a sign that he wants the territory's new leader, Carrie Lam, whose inauguration the Chinese president oversaw during his trip, to take a hard line with local democracy activists.
He has hinted that he wants the Hong Kong government to introduce an anti-subversion law, which has long been a contentious issue in the territory, prompting riots in 2003 when the government first tried to introduce it.
He also wants Ms Lam to introduce more "patriotic education", despite the street demonstrations in 2012 when the government tried to introduce history lessons that were approved by the Chinese Communist Party.
Additional reporting: Agencies