BEIJING, China — China on Wednesday vowed zero tolerance for "separatist activities" in Taiwan and reaffirmed that it would take the self-ruled island by force if necessary.
The warning from Beijing, which considers Taiwan its territory, came after days of unprecedented Chinese military drills around the island sparked by a trip there by US House Speaker Nancy Pelosi.
Pelosi stood by her visit, saying she was "very proud" of her delegation and believed China had used her visit as a "pretext" to launch its military exercises.
"We will not allow China to isolate Taiwan," Pelosi told reporters in Washington.
Pelosi last week became the highest-ranking US official to visit Taiwan in decades despite stark threats from China, which tries to keep Taipei isolated on the world stage.
China's Taiwan Affairs Office on Wednesday issued a white paper laying out how it intends to claim the island through a range of economic incentives and military pressure.
"We are ready to create vast space for peaceful reunification, but we will leave no room for separatist activities in any form," said the paper.
China will "not renounce the use of force, and we reserve the option of taking all necessary measures".
It added, however: "We will only be forced to take drastic measures to respond to the provocation of separatist elements or external forces should they ever cross our red lines."
China last issued a white paper on Taiwan in 2000.
Taiwan's Mainland Affairs Council, the island's top policymaking body on China, rejected the paper and said the document "is full of... lies".
"Taiwan maintains that 'neither side belongs to the other', and firmly refuses 'one country, two systems' -- this is the current status of the Taiwan Strait and the reality," it said in a statement.
"One country, two systems" refers to the model under which Hong Kong and Macau were promised a degree of autonomy under Chinese rule. It has been proposed by Beijing as a solution for Taiwan.
The release of the white paper came on the same day that a top Taiwan opposition politician flew to China for meetings with Taiwanese businesspeople, prompting condemnation from Taipei which had called on him to cancel the trip.
Andrew Hsia, deputy chairman of the Beijing-friendly Kuomintang party, travelled to China with a delegation in an unofficial capacity and was not scheduled to visit the capital.
He will quarantine for 10 days and return to Taiwan on August 27, the party said in a statement.
But President Tsai Ing-wen criticised him for travelling across the Taiwan Strait after days of Chinese military drills around the island.
"At this moment, the Kuomintang still insisted on going to China, disappointing our people. The Kuomintang's actions are also sending the wrong message to the international community," Tsai told a meeting of her ruling party on Wednesday.
Since the late 1990s, the island has transformed from an autocracy into a vibrant democracy, and a distinct Taiwanese identity has emerged.
Relations between the two sides have significantly worsened since Tsai became president in 2016.
Tsai and her Democratic Progressive Party do not consider Taiwan to be part of China.
Their platform falls under China's broad definition of Taiwanese separatism, which includes those who advocate for the island to have an identity separate from the mainland.
Invasion fears
The Chinese white paper promised Taiwan economic prosperity as well as "greater security and dignity" after "reunification".
But that offer comes in the shadow of the biggest military exercises China has ever conducted around the island, including training for a blockade.
The drills have raised fears that China's Communist leadership could be preparing for an invasion.
The exercises were initially expected to conclude on Sunday, but have continued this week.
China's People's Liberation Army said Wednesday it would "continue to carry out military training and prepare for war", without specifying whether more drills had been conducted that day or if there would be further exercises.
But Taiwan's defence ministry said it detected 36 Chinese warplanes and 10 ships operating around the strait on Wednesday, conducting joint air-sea operations.
Seventeen planes crossed the median line -- an unofficial demarcation between China and Taiwan that Beijing does not recognise.
The ministry added that the Taiwanese military "will adjust how we deploy our forces... without letting our guard down".
Taipei has accused China of using the Pelosi visit as an excuse to rehearse for an invasion and has conducted its own military drills to prepare for an attack on the island.