China will set up a brief no-fly zone north of Taiwan on Sunday due to what the island's transport ministry described as "space activities".
The closure comes after Beijing completed three days of massive war games around self-ruled Taiwan last week, during which China simulated targeted strikes and practised a blockade of the island.
The no-fly zone does not appear to be linked to the drills, with Taiwan's transport ministry saying on Wednesday China had imposed the restriction "on the convergence areas of many international routes" on the grounds of "space activities".
The restrictions will be in place from 9:30 am to 9:57 am (0130 to 0157 GMT) on Sunday.
The transport ministry said China had initially announced a three-day closure but revised it following objections from Taipei.
The ministry had informed China "this unreasonable designation will bring huge and unnecessary flight risks to the region, and damage the rights and interests of international aviation", it said.
Taiwan's Lieutenant General Yen Yu-hsien said the no-fly zone was within Taiwan's air defence identification zone (ADIZ).
"It's around 85 nautical miles off the north of Taiwan," he told a news briefing.
"In the north, there are many international flight routes, including to Japan, Korea and the US."
Japan's top government spokesperson said Tokyo had also been notified of the no-fly zone.
"Chinese authorities notified us of the designation of an area that may affect the safety of aircraft flights for aerospace activities from April 16 to 18," Hirokazu Matsuno said.
China's defence ministry and civil aviation authority did not respond immediately to a request for comment.
Beijing's space ambitions have become increasingly bold in recent years, successfully landing a rover on Mars, bringing samples back from the Moon and planning a lunar space station with Russia.
Taiwan has been on high alert since China launched its military drills on Saturday.
The exercises ended on Monday when Beijing sent 54 aircraft into the island's southwestern and southeastern ADIZ -- the highest recorded in a single day since October 2021.
The zone is not the same as Taiwan's territorial airspace and includes a far greater area that overlaps with part of China's own ADIZ and even some of the mainland.
J15 fighter jets flown off China's Shandong aircraft carrier were among the aircraft that crossed the median line, an unofficial boundary in the Taiwan Strait, Taiwan's defence ministry said.
The ministry also said eight warships and 35 aircraft were detected between Tuesday and Wednesday morning, after the war games ended.