China's navy will carry out exercises in the Pacific Ocean in the coming days, amid continuing tension over maritime disputes in the region.
The defence ministry said the drills were routine and were not targeting any specific country.
China is locked in territorial rows with several nations, and the US has recently made a series of announcements bolstering its presence in the region.
A Pentagon spokesman said the US had no problem with the naval exercises.
Captain John Kirby said that China was "entitled to exercise their military in ways they deem fit".
A short statement on the defence ministry's website announced the exercises late on Wednesday.
"This is an annual, planned, routine drill. It is not directed at any specific country or target and is in keeping with relevant international laws and practices," said the statement.
"China's freedom of navigation and other legal rights should not be obstructed."
Japanese defence officials reported seeing six warships sailing in international waters near the country's southern Okinawa prefecture.
China has clashed with several other nations in the South China Sea, where countries including Vietnam and the Philippines have overlapping claims.
US President Barack Obama announced last week that the US was boosting its presence in the region, and will base a full Marine task force in northern Australia.
Analysts say the US move is a direct challenge to China's attempts to dominate the area, and is likely to bolster US allies in the South China Sea dispute.