The Chinese government has accused the United States of trespassing after Navy destroyer the USS Stethem (pictured above) came within 12 nautical miles of the disputed Triton Island in the Paracel Islands archipelago.
The island is claimed by China, Taiwan and Vietnam, and 12 nautical miles is commonly accepted as constituting the territorial waters of a landmass.
China sent military vessels and fighter planes in response to the US' latest "freedom-of-navigation" operation, Foreign Ministry spokesman Lu Kang said, according to state news agency Xinhua. "Beijing will continue to take all necessary means to defend national sovereignty and security."
China's Defense Ministry responded in a statement Monday, saying that the actions of the US navy had seriously damaged the "political atmosphere" surrounding the development of military ties between the two countries. It added that it resolutely opposes the entry of US warships into Chinese territory.
The US operation came just hours before a scheduled phone call between President Donald Trump and his Chinese counterpart, Xi Jinping.
Strain to US-Chinese relations
The US does not recognize Beijing's claim to sovereignty over the Paracel Islands, which China has occupied and on which it is building fortifications.
"I believe the Chinese are building up combat power and positional advantage in an attempt to assert de facto sovereignty over disputed maritime features and spaces in the South China," Admiral Harry Harris, head of the US Pacific Command, said last week.
This is the second such operation since Trump took office, in a further strain to US-Chinese relations. On May 25, the USS Dewey guided-missile destroyer sailed less than 12 nautical miles from Mischief Reef, part of the disputed Spratly Islands in the South China Sea, south of the Paracels.
Last Thursday, Trump authorized a $1.3-billion (1.2-billion-euro) arms sale to Taiwan and the US administration imposed sanctions on two Chinese citizens and a shipping company for helping North Korea's nuclear and missile programs, as well as a Chinese bank accused of laundering North Korean cash.
Two days earlier, the State Department also put China on a list of the world's worst human trafficking offenders.