The Chinese Navy began a three-day series of exercises in the South China Sea on Wednesday, the Maritime Safety Administration said.
It released the coordinates of the drill zone - a rectangular area off Hainan province's southern coast - on its website on Tuesday, asking ships to stay out of the area.
The information sparked a wave of speculation among Chinese military enthusiasts who, since last month, have been talking on internet forums about the possibility of a large display of the Navy's best ships and submarines in the South China Sea. Some fans also posted what they claimed were satellite images of a vast armada of Chinese ships, including the CNS Liaoning aircraft carrier, gathering recently in the South China Sea area.
The Navy said last month that it would conduct combat exercises there "in coming days", noting that the drills are part of its annual training regimen.
Whether that was a reference to the exercises that began on Wednesday wasn't known. There have been no reports of other naval operations in the South China Sea. Navy publicity officials reached by China Daily declined to elaborate.
The Chinese military has emphasized combat drills and joint operations since President Xi Jinping, who is also chairman of the Central Military Commission, took office in late 2012.
All the Navy's combat ships and submarines now spend around eight months each year at sea, carrying out patrols, drills and other training operations - much longer than before. As a result, their operational capabilities have improved substantially, the Navy said.
In 2017, the Navy commissioned at least 16 ships, mostly large combat vessels. China is now building its second aircraft carrier and a new-generation guided-missile destroyer believed to be the most powerful of its kind in the world.