Tensions continue to rise as an argument breaks out over Taiwan's median line, which China says does not exist.
China's Vice Foreign Minister Ma Zhaoxu told reporters the "median line" - an unofficial buffer separating Taiwan from the mainland - isn't real.
It comes as about 20 Chinese and Taiwanese naval vessels remained close to the maritime border earlier today.
A source briefed on the matter said China continues to conduct missions off the self-ruled island's eastern coast.
Mr Zhaoxu told state-linked outlet CCTV: "Taiwan is part of China's territory.
"There is no such thing as a median line in the Strait."
He added: "The Chinese armed forces conduct military exercises in waters off China's Taiwan island to safeguard sovereignty and territorial integrity of China. Our measures are open and proportionate.
"They are in line with both domestic law and international law and practices. They are beyond reproach.
"The US and its allies often come to the adjacent waters of China, flexing muscles and stirring up troubles [sic].
"They conduct up to 100 military exercises each year.
"They, instead of someone else, are the ones that overreact and escalate the situation."
Meanwhile, the Chinese embassy in London has condemned what it called Britain's "irresponsible rhetoric" after Foreign Secretary Liz Truss summoned its ambassador over Beijing's actions towards Taiwan.
Truss summoned Zheng Zeguang earlier on Wednesday, saying China's "increasingly aggressive behaviour" following U.S. House Speaker Nancy Pelosi's visit was threatening peace and stability in the region around Taiwan.
Zheng "firmly rejected & strongly condemned UK side's irresponsible rhetoric about China's legitimate & necessary response to US House Speaker's Taiwan visit" in a meeting with a senior British foreign ministry official, the Chinese embassy said on Twitter.
"Taiwan is an inseparable part of China's territory. No foreign country, UK included, has the right to meddle with the internal affairs of China."
China's military has "completed various tasks" around Taiwan but will conduct regular patrols, it also said today.
The comments potentially signalled an end to days of war games but also that Beijing will keep its pressure on the island.
Furious at a visit to Taipei last week by U.S. House Speaker Nancy Pelosi, China had extended its largest-ever exercises around the self-ruled island it claims as its own beyond the four days originally scheduled.
Last week's drills included launches of ballistic missiles, some of which flew over the island's capital of Taipei, and simulated sea and air attacks in surrounding skies and waters.
In a brief statement, the Eastern Theatre Command of the People's Liberation Army said its joint military operations around Taiwan had "successfully completed various tasks and effectively tested the integrated combat capabilities of the troops".
It added: "Theatre forces will keep an eye on the changes in the situation in the Taiwan Strait, continue to carry out training and preparation for combat, organise regular combat readiness patrols in the direction of the Taiwan Strait, and resolutely defend national sovereignty and territorial integrity."
Taiwan Defence Ministry spokesman Sun Li-fang said in response to China's statement that under the premise of not relaxing combat readiness, Taipei would "fully adjust the allocation of forces based on factors such as the enemy threat".
Video from state broadcaster CCTV on Wednesday showed Chinese fighter jets scrambling and refuelling in mid-air, as well as navy ships on what it said were drills around Taiwan.
China's military said the drills were focused on blockades and resupply logistics, "under a complex electromagnetic environment to refine joint containment and control capabilities", according to CCTV.
