A US Navy warship sailed near a disputed island in the South China Sea on Sunday (2 July), making Beijing's hackles rise. China accused Washington of trespassing its territorial waters and called the move a "serious political and military provocation".
According to Fox News, which first reported the operation, the USS Stethem sailed within 12 nautical miles of Triton Island, part of the Paracel Islands in the hotly contested waters.
While China has occupied the island, Vietnam and Taiwan too have overlapping claims on the territory. The US is said to have challenged the claims of all the three countries by sailing in these waters.
China refers to Paracel islands as Xisha and Vietnam calls it Hoàng Sa. Beijing took full control of the island in 1974 after it forced the-then South Vietnamese navy off its holdings, according to Reuters.
China's Ministry of Foreign Affairs accused the US destroyer of making an unauthorised entry into the waters it controls.
Beijing had dispatched warships and fighter jets to warn off the USS Stethem during the operation, the ministry said in a statement late on Sunday (2 July).
"China strongly urges the US side to immediately stop this kind of provocative action which seriously violates China's sovereignty and puts at risk China's security," ministry spokesman Lu Kang said.
He added that the communist country would take all necessary measures to defend its national security and sovereignty.
The so-called freedom of navigation operation, or fonop, affirming the right to passage, is the second such action by the US Navy under Donald Trump's presidency. The first was when the USS Dewey, a guided-missile destroyer, carried out a "manoeuvring drill" when it conducted a fonop operation within 12 nautical miles of the Mischief Reef in the Spratly Islands.
The US conducted the fonop just hours before President Donald Trump was due to speak to his Chinese counterpart Xi Jinping and Japanese Prime Minister Shinzo Abe over telephone.
According to a UN ordinance, 12 nautical miles beyond the shore of all the claimant countries marks the territorial limits recognised internationally. By sailing within those limits, the US is suggesting it does not recognise territorial claims there, Fox News noted.
Washington's patrol has infuriated Beijing considering the US is not a claimant in the territorial dispute in the mineral-rich South China Sea. However, the US says its patrols are aimed at showing support for free passage to vessels in international waters.
The sailing came at a time when the Trump administration is relying on China to rein in an increasingly belligerent North Korea. However, the US Pacific Command is also thought to be keen on admonishing Beijing as an aggressor in the strategic waterway.