Taiwan is protesting China's decision to change a route flown by its civil aircraft, bringing it closer to the median line of the Taiwan Strait, starting from Thursday.
China's civil aviation authorities announced it would restore the southbound route to its original flight path on Tuesday. China introduced the route in 2015, but has operated flights closer to the continent after Taiwan negotiated for an adjustment due to security concerns.
China began the northbound operation of the route in 2018.
Taiwan's Liberty Times says the latest adjustment means Chinese commercial planes can fly as close as 7.8 kilometers from the median line.
Chinese civil aviation authorities say the route is situated in the Shanghai Flight Information Region. They said the route change is routine work and was needed to deal with an increasing number of flights and to reduce delays.
The Taiwanese authorities strongly protested China's unilateral announcement. They expressed suspicion that Beijing is attempting to use civil aviation as a cover for political and military intentions aimed at altering the status quo in the Taiwan Strait.
China's military planes have been crossing the median line on a regular basis. Observers say the announced route change may be part of Beijing's attempt to undermine the significance of the line.