Beijing lashes out at US for South China Sea sail-by

The U.S. and its allies periodically send planes and warships through the area to conduct "freedom of navigation" operations, intended as a signal to Beijing of their right under international law to pass through the waters claimed by China.

According to the Pentagon, the USS Chancellorsville guided-missile destroyer sailed Monday near the Paracel islands, known as Xisha in Chinese, "to challenge excessive maritime claims and preserve access to the waterways as governed by international law."

The Chinese military scrambled aircraft and warships, sending out warnings for the American vessel to leave the area.

"We urge the U.S. to strengthen the management of its vessels and aircraft that pass by Chinese territory to prevent unexpected events," People's Liberation Army Southern Theatre spokesman Li Huamin said in a statement.

China has also lodged a diplomatic complaint with Washington, foreign ministry spokesman Geng Shuang said during a regular press briefing, calling on the U.S. to "immediately stop such provocative actions that violate China's sovereignty".

China claims nearly all of the South China Sea, including waters close to Taiwan, the Philippines, Brunei, Malaysia and Vietnam. The waterway is known as the East Sea in Vietnam.

Further angering those countries, and the U.S., Beijing has moved aggressively to build up reefs into artificial islands capable of hosting military planes.

It was the second U.S. naval operation to irk China this week.

On Wednesday, two U.S. ships sailed through the Taiwan Strait -- which China considers its territory but the U.S. and others see as international waters open to all -- prompting a furious Beijing to send warships and fighter jets.

This was the third such operation this year, including one last month which prompted a diplomatic protest.

"U.S. Forces operate in the Indo-Pacific region on a daily basis, including the South China Sea," the Pentagon statement read.

"All operations are designed in accordance with international law and demonstrate that the United States will fly, sail and operate wherever international law allows."

The naval tensions come just ahead of scheduled talked between U.S. President Donald Trump and Chinese leader Xi Jinping at the G20 summit in Argentina this weekend aimed at softening trade tensions.