China today sent warships and dozens of fighter jets toward Taiwan in a "serious warning" to any citizens who want to make the island's de facto independence permanent.
The Chinese military announced the start of three-day "combat readiness patrols" which today saw eight warships and 71 planes fly across the middle line of the strait that separates Taiwan from the mainland.
Taiwan's Ministry of Defence said they included Chengdu J-10, Shenyang J-11 and Shenyang J-16 jet fighters.
It is feared previous exercises, which saw missiles fired into the sea and the disruption of shipping and airline flights, may be repeated as part of China's move.
The People's Liberation Army (PLA) said: "This is a serious warning against the collusion and provocation between the Taiwan independence' separatist forces and external forces." The "Joint Sword" exercises "defend national sovereignty and territorial integrity," it added.
The Taiwanese military said missile defense systems were activated and air and sea patrols sent to track the Chinese aircraft.
"We condemn such an irrational act that has jeopardised regional security and stability," a Ministry of Defence statement said.
The US House of Representatives speaker, Kevin McCarthy, held talks with Taiwan President Tsai Ing-wen on Thursday in California, adding to a series of foreign lawmakers who have met Tsai to show support in the face of Chinese intimidation.
Beijing responded Friday by imposing a travel ban and financial sanctions against American groups and individuals associated with Tsai's U.S. visit.
But, in addition to the deployment of warships today, the navy in China plans to hold "live fire training" in Luoyuan Bay in Fujian province opposite Taiwan.
Ships were banned during the firing, which also was due to take place on five dates over the next two weeks, the local Maritime Authority announced.
Taiwan split with China in 1949 after a civil war. 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.
The United States has no official relations with Taiwan, a centre for high-tech industry and one of the biggest global traders, 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.
Military analysts suggest a possible Chinese strategy in the event of an attack is to try to pressure Taiwan to surrender by blocking sea and air traffic, preventing the United States, Japan or other allies from intervening or sending supplies.
On Saturday, the PLA was testing its ability to dominate the sea, air and information and to "create a situation of deterrence and suppression," the mainland newspaper The China Daily said.
Taiwan and the mainland have multibillion-dollar trade and investment ties but no official relations.
"We will never leave room forTaiwan 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," Zhu was quoted as saying Friday.
