China has sent warships and dozens of fighter jets towards Taiwan, the island’s government said.
The move came in retaliation for a meeting between the US House of Representatives speaker and the president of the self-ruled island democracy claimed by Beijing as part of its territory.
The Chinese military announced the start of three-day “combat readiness patrols” as a warning to Taiwanese who want to make the island’s de facto independence permanent.
The People’s Liberation Army (PLA) gave no indication whether they might include a repeat of previous exercises with missiles fired into the sea, which disrupted shipping and airline flights.
Beijing responded on Friday by imposing a travel ban and financial sanctions against American groups and individuals associated with Ms Tsai’s US visit.
On Saturday, eight warships and 42 planes were detected near Taiwan, 29 of which crossed the middle line of the strait that separates the island from the mainland, Taiwan’s Ministry of Defence said.
The planes included Chengdu J-10, Shenyang J-11 and Shenyang J-16 jet fighters.
Taiwan split from China after a civil war in 1949. The ruling Communist Party says the island is obliged to rejoin the mainland, by force if necessary. Beijing says contact with foreign officials encourages Taiwanese who want formal independence, a step the ruling party says would lead to war.
“This is a serious warning against the collusion and provocation between the ‘Taiwan independence’ separatist forces and external forces,” said a PLA statement. The “Joint Sword” exercises are a “necessary action to defend national sovereignty and territorial integrity”.
“We condemn such an irrational act that has jeopardised regional security and stability,” a Ministry of Defence statement said.
Chinese president Xi Jinping’s government has stepped up efforts to intimidate the island by flying fighter jets and bombers nearby and firing missiles into the sea.
The United States has no official relations with Taiwan’s government but maintains extensive informal and commercial ties. Washington is required by federal law to ensure the island of 22 million people has the means to defend itself if China attacks.
Taiwan and the mainland have multibillion-dollar ties of trade and investment but no official relations.
“We will never leave room for ‘Taiwan independence’ separatist activities in any form and will definitely take resolute measures to defeat any foreign interference,” said a spokesperson for the Cabinet’s Taiwan Affairs Office, Zhu Fenglian, according to the official Xinhua News Agency.
“Complete reunification of our country must be realised, and it can, without doubt, be realised,” Mr Zhu was quoted as saying on Friday.