China's first domestically built aircraft carrier has begun sea trials.
The still-unnamed ship left the northern port of Dalian early Sunday to "test the reliability and stability of its propulsion and other system,'' the Defense Ministry said in a statement.
The 50,000-ton carrier will likely be formally commissioned sometime before 2020 following the completion of sea trials and the arrival of its full air complement.
The ship's design is based on the former Soviet Union's Kuznetsov class, with a ski jump-style deck for taking off and a conventional oil-fueled steam turbine power plant.
The carrier will be the second to enter the Chinese navy. The first, the Liaoning, was bought second-hand from Ukraine, refitted in China and commissioned in 2012.
State media reports say China is also planning to build a nuclear-powered aircraft carrier capable of remaining at sea for long durations.
China has the world's largest navy in terms of numbers of ships, although it lags far behind the U.S. in technology and combat capabilities.
The Chinese military has undergone rapid modernization since President Xi Jinping took power five years ago.
The Chinese navy, especially, has been used to assert Beijing's claim to virtually the entire South China Sea and is increasingly ranging farther into the Pacific and Indian oceans.
Last year, China established its first overseas military base in the Horn of Africa nation of Djibouti, where rivals such as the U.S., Japan and several European nations also have a permanent presence.