TAIPEI, Taiwan — China launched its first domestically built aircraft carrier to begin sea trials on Sunday, reaching another milestone in the expansion of the country’s navy.

The aircraft carrier, as yet unnamed, left its berth at a shipyard in the northeastern port of Dalian after a blow of its horn and a display of fireworks, according to reports in state news media.

The Chinese Navy — officially the People’s Liberation Army Navy — already has one operational carrier, the Liaoning, which it bought unfinished from Ukraine after the collapse of the Soviet Union. That ship joined the Chinese fleet in 2012 and began its first operations four years later, putting China in the small group of seafaring powers that maintain aircraft carriers, led by the United States, which has 11.

The Liaoning, which appears to serve as a training vessel as much as a combat ship, was the centerpiece of a naval parade of 48 ships attended last month by China’s leader, Xi Jinping. The following week, it led a carrier battle group in live-fire exercises in the Taiwan Strait and in the East China Sea.