Chinese first aircraft carrier Shi Lang on Wednesday left its shipyard in the country's northeast to start its first sea trial, the state news agency Xinhua said.
The revamped old Soviet ship's sea trial was in line with the schedule of its refitting project and would not take long, the news agency said, quoting military sources.
After returning from the trial, the carrier will continue its refit and test work, the report said, adding that the vessel had set sail from its shipyard in the city of Dalian.
Beijing last month sought to downplay the capability of its first aircraft carrier, saying the vessel would be used for training and "research", amid concerns over the country's military build-up.
The project has added to regional worries over the country's fast military expansion and growing assertiveness on territorial issues.
It also comes amid heightened tensions over a number of maritime territorial disputes involving China, notably in the South China Sea, which is believed to be rich in oil and gas and is claimed by several countries.
The issue has heated up recently with run-ins between China and fellow claimants Vietnam and the Philippines, sparking concern among its neighbouring countries and the United States.
In September, a erupted between Japan and China over the disputed Senkaku Islands, known as the Diaoyu Islands in Chinese, located in the East China Sea.
Chen Bingde, the nation's top military official, only provided the first official acknowledgement of the aircraft carrier in a Hong Kong newspaper interview in early June.
But media reports and military analysts have for years said the 300-metre (990-foot) ship was in development.
The ship, once called the Varyag, was originally built for the Soviet navy. Construction was interrupted by the collapse of the Soviet Union in 1991.
China reportedly bought the ship's immense armoured hull -- with no engine, electrics or propeller -- in 1998.
China's People's Liberation Army -- the largest armed force in the world -- is extremely secretive about its defence programmes, which benefit from a huge and expanding military budget boosted by the nation's runaway economic growth.
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