0951 GMT December 14, 2019
The ship, which has yet to be named, is Beijing's second carrier and will add massive firepower to its navy once it is officially put into service, as the country faces tensions with self-ruled Taiwan and regional neighbors around the South China Sea, according to AFP.
The carrier crossed the sensitive waters on Sunday before entering the South China Sea for "scientific research tests and routine training", navy spokesman Cheng Dewei said on an official social media account.
Cheng said it was "normal practice" for carriers that are under testing to conduct cross-regional trials.
"It is not aimed at any specific target and has nothing to do with the current situation," Cheng said without elaborating.
The sail-by comes as Taiwan gears up for presidential elections in January.