Updated

China's first aircraft carrier has successfully completed sea trials in the South China Sea, state media reported.

The Liaoning returned to port Wednesday after a 37-day voyage, the official Xinhua News Agency said. Citing an unnamed naval source, Xinhua said the aircraft carrier tested its combat system and conducted a formation practice and "attained the anticipated objectives."

"All tests and training programs went well as scheduled," it said.

Aircraft, naval vessels and submarines also participated in the Liaoning's tests.

Early in the Liaoning's trial run, one of the Chinese ships accompanying it was involved in a near collision with a U.S. Navy ship. A Chinese media report blamed the U.S. ship getting too close to the Liaoning, while U.S. Defense Secretary Chuck Hagel called China's behavior "irresponsible." It marked the two countries' most serious sea confrontation in years.

The Liaoning was bought from Ukraine more than a decade ago and extensively refurbished before entering service in 2012.

China claims virtually the entire South China Sea. A recent expansion of its naval reach has challenged the decades-old American dominance and alarmed its smaller neighbors, particularly the Philippines and Vietnam, which have competing territorial claims with Beijing to a string of islands.