Beijing rebutted Washington's accusation on Friday over Chinese military activity in the South China Sea, and urged the United States to stop stirring up trouble in the area.

Foreign Ministry spokesman Zhao Lijian made the remark after the US Defense Department said Thursday that Chinese test launches of ballistic missiles in the South China Sea were threatening peace and security in the region.

Such accusations are groundless and unreasonable as Chinese military exercises near the Xisha Islands are routine arrangements, which target no third country and have nothing to do with the disputes over the South China Sea issue, the spokesman said.

According to local maritime safety administrations, China is holding naval drills in all four of its major adjacent waters－the Bohai Sea, Yellow Sea, East China Sea and South China Sea. Recently, the Chinese military has conducted several drills in these waters.

The US has repeatedly dispatched advanced warships and aircraft to the South China Sea to flex its muscles, and the military provocations have damaged China's sovereignty and security interests, Zhao said.

"The US is a destroyer and troublemaker of peace and stability in the South China Sea, which has been witnessed by the international community," he said.

Zhao urged Washington to stop inciting trouble in the South China Sea and cease driving a wedge between regional countries, and instead play a constructive role in maintaining regional peace and stability.

Earlier on Friday, Senior Colonel Li Huamin, spokesman for the People's Liberation Army Southern Theater Command, said in a statement that the theater command expelled a US warship that trespassed into Chinese territorial waters off the Xisha Islands.

The US guided missile destroyer USS Mustin trespassed into the waters on Thursday and the PLA Southern Theater Command dispatched naval and air forces to track, identify and warn it to leave, Li said.

The US has ignored international law and repeatedly stirred up trouble in the South China Sea under the pretense of "freedom of navigation", Li said. These actions have seriously undermined China's sovereignty and security interests, as well as order in the region, he added.

"We urge the US to stop such provocative actions and strictly manage the activities of its naval and air force assets and personnel to avoid possible military accidents," Li said.

"China has undisputable sovereignty over the islands in the South China Sea and their adjacent waters in the region," he said."The troops are always on high alert to resolutely safeguard national sovereignty, as well as peace and stability in the South China Sea.