China launches first home-built aircraft carrier amid South China Sea tension

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.

Taiwan, claimed by Beijing as its own, has said China is actually building two new aircraft carriers, but China has not officially confirmed the existence of another carrier.

Chinese state media has quoted experts as saying that the country needs at least six carriers. The United States operates 10 and plans to build two more.

Major General Chen Zhou, a researcher at the Academy of Military Science, told reporters in March that China would not exceed the United States in carrier groups. "China has no need for this," he said.

Sam Roggeveen, a senior fellow at the Sydney-based Lowy Institute, said that by the time China had half that number, it could go toe-to-toe with the U.S. navy in the AsiaPacific.

"Given that the Americans have global obligations and responsibilities but China doesn't, then effectively by that point they would be evenly matched," Roggeveen said.

Most experts agree that developing such a force will be a decades-long endeavor but the launch of the second carrier holds a certain prestige value for Beijing, seen by many analysts as keen to eventually erode U.S. military prominence in the region.

"With two aircraft carriers you could say without much fear of contradiction that China, other than the United States, is the most powerful maritime force in the AsiaPacific," Roggeveen said.