China has begun four days of live-fire naval exercises in the Yellow Sea.
The drill is scheduled to end Saturday -- a day before the United States and South Korea begin their own exercise in the same body of water.
The official Xinhua news agency quoted China's defense ministry saying this week's exercise is taking place near the city of Qingdao. It was described as a routine training event involving mainly the shooting of shipboard artillery.
The drill is the latest in a series of naval exercises involving the United States, China and South Korea that have heightened tensions in the region. It also comes as high-ranking Chinese military officers are in North Korea to discuss closer military ties.
China opposes any U.S. military activity in the Yellow Sea, which lies between China and the Korean peninsula.
In July, the United States and South Korea moved a major naval exercise from the Yellow Sea to the Sea of Japan following Chinese objections. China followed with a naval exercise of its own in the Yellow Sea.
Next week's U.S.-South Korean exercise will take place in the Yellow Sea, but will not involve the aircraft carrier USS George Washington, whose participation in the earlier drill particularly troubled China.
The United States says the George Washington will conduct maneuvers in the Yellow Sea sometime later this year.
The United States says its exercises are aimed not at China, but at North Korea, which it accuses of sinking a South Korean warship in March. North Korea denies any responsibility for the sinking of the Cheonan, which killed 46 sailors.
China and North Korea, meanwhile, are exploring closer military cooperation. Xinhua reported that Zhang Youxia, a commander of the People's Liberation Army, was in Pyongyang on Wednesday for talks.
Some information for this report was provided by AFP, Reuters, BBC and Xinhua