China begins military exercises in Yellow Sea
The Chinese navy has begun artillery exercises in the Yellow Sea, days before the US and South Korea hold similar manoeuvres there.
State media called the drills "annual routine training, mainly involving the shooting of shipboard artillery".
China opposes the joint US-South Korea exercises, the latest of which begins on 5 September.
Those drills are intended as a show of force to North Korea, following the sinking of a South Korean warship.
The Cheonan went down on 26 March near the inter-Korean border with the loss of 46 lives.
International investigators say a North Korean torpedo sank the ship, but Pyongyang denies any role in the sinking.
The Chinese exercises are taking place off the eastern city of Qingdao, Xinhua news agency said, and are due to run until 4 September.
China also held air exercises over its east coast in August, in what was seen as a response to the joint US-South Korea drills.
Washington and Seoul are engaging in a series of exercises in the wake of the Cheonan incident, some of which are taking place in the Yellow Sea, which lies between the Korean peninsula and China.
The latest drill, which will run until 9 September, "will focus on anti-submarine warfare tactics, including detecting and destroying North Korean submarines", an unidentified military official told South Korea's Yonhap news agency.
China says the drills could destabilise the region and strongly opposes them.
They also come at a time of tension between China and several nations over conflicting territorial claims in regional seas.
In July US Secretary of State Hillary Clinton angered Beijing when she said a peaceful resolution of territorial disputes between China and several South East Asian nations in the South China Sea was a "national interest" of the US.