China launched its first indigenously built aircraft carrier Wednesday in a move that showcases the country's growing maritime clout amid simmering tensions over the disputed South and East China seas.

The 50,000-ton carrier was transferred from a dry dock into the water at a launch ceremony at the Dalian shipyard in the northeastern province of Liaoning, China's Defense Ministry said.

The ceremony was attended by Fan Changlong, vice chairman of the powerful Central Military Commission, as well as top navy officials, which came just three days after the anniversary of the People's Liberation Army Navy's symbolic founding in 1949.

The Defense Ministry said navy commander Vice Adm. Shen Jinlong, a former commander of the South Sea Fleet who oversees defending China's claim to much of the South China Sea, was also in attendance.

China's only other carrier is the Liaoning, a refitted Soviet ship that was commissioned into China's navy in 2012.

China began building its second carrier in November 2013, with dock construction starting in March 2015, the official Xinhua News Agency said. The main body of the carrier has been completed, with major systems equipment installed.

It is expected to be formally commissioned sometime before 2020, after sea trials and the arrival of its full air complement.

The new carrier's name and hull code have yet to be released. The navy usually makes such information public once a ship is commissioned.

"Putting the carrier into water marked progress in China's efforts to design and build a domestic aircraft carrier," Xinhua said in its report.

The next phase will see the carrier begin the outfitting process, the state-run China Daily newspaper said. During the outfitting stage, engineers and workers will complete the installation of the ship's power plant, engines, interior equipment and systems, as well as its weapons.

The China Daily called the ship "the largest and most sophisticated surface vessel China has ever built."

Like the 60,000-ton Liaoning, which was purchased from the Ukraine, the new carrier — known as the Type 001A — is based on the Soviet Kuznetsov-class design, with a ski jump-style deck for taking off and a conventional oil-fueled steam turbine power plant. That limits the weight of payloads its planes can carry, its speed and the amount of time it can spend at sea relative to U.S. nuclear-powered carriers.

China is believed to be planning to build at least two and possibly as many as four additional carriers, with one of them, the Type 002, reported to be already under construction at a shipyard outside Shanghai. They are expected to be closer in size to the U.S. Navy's nuclear-powered 100,000-ton Nimitz-class ships, with flat flight decks and catapults to allow planes to launch with more bombs and fuel aboard.

China's navy has been taking an increasingly prominent role in recent months, with a rising-star admiral taking command, its first aircraft carrier sailing around Taiwan and new Chinese warships popping up in far-flung areas.

The Liaoning has taken part in military exercises, including in the South China Sea, but is expected to serve more as a training vessel. State media has said the new carrier will be more dedicated to military and humanitarian operations.

China claims almost all the South China Sea, believed to have huge deposits of oil and gas, through which about $5 trillion in ship-borne trade passes every year, and has been building up military facilities like runways on the islands it controls.

Brunei, Malaysia, the Philippines, Taiwan and Vietnam also have claims.

Beijing is also at odds with Tokyo over the Japanese-controlled Senkaku Islands in the East China Sea. Those tiny islets are known as the Diaoyus in China.

Information from AP and Reuters added