BEIJING/HONG KONG — A United States Navy warship sailed close to a disputed reef in the South China Sea yesterday, said a US Department of Defense official, prompting anger in Beijing, which denounced the patrol as illegal and a threat to peace and stability.

The guided-missile destroyer USS William P Lawrence travelled within 12 nautical miles of Chinese-occupied Fiery Cross Reef in the Spratly archipelago, said Defense Department spokesman Bill Urban. The so-called freedom-of-navigation operation was undertaken to “challenge excessive maritime claims” by China, Taiwan, and Vietnam which were seeking to restrict navigation rights in the South China Sea, he said.

“These excessive maritime claims are inconsistent with international law as reflected in the Law of the Sea Convention in that they purport to restrict the navigation rights that the United States and all states are entitled to exercise,” said Mr Urban in an emailed statement.

This is Washington’s third freedom-of-navigation operation in the disputed waters in recent months.

Beijing and Washington have previously traded accusations that the other is militarising the South China Sea as China undertakes large-scale land reclamation and construction on the waterway while the US has increased its patrols and exercises in the region.

Chinese Foreign Ministry spokesman Lu Kang said yesterday the US ship illegally entered Chinese waters.

“China hereby expresses dissatisfaction and opposition,” he told a daily news briefing. “This action by the US side threatened China’s sovereignty and security interests, endangered the staff and facilities on the reef, and damaged regional peace and stability.”

The US operation came on the heels of a Chinese military combat drill on Sunday and Monday, reported the South China Morning Post, whereby the South Sea Fleet of the People’s Liberation Army led a garrison to conduct an attack and defence exercise off Subi Reef, also in the Spratly Islands.

China claims most of the South China Sea, through which about US$5 trillion (S$6.9 trillion) in ship-borne trade passes every year. Vietnam, Malaysia, Brunei, the Philippines and Taiwan have rival claims.

The Pentagon last month called on China to reaffirm it has no plans to deploy military aircraft in the disputed Spratly Islands after Beijing used a military plane to evacuate sick workers from Fiery Cross Reef.

Facilities on Fiery Cross Reef include a 3km runway which is one of three China has been building up for more than a year by dredging sand onto reefs and atolls in the Spratlys. Washington is concerned China will use it to press its extensive territorial claims at the expense of weaker rivals.

“Fiery Cross is sensitive because it is presumed to be the future hub of Chinese military operations in the South China Sea, given its already extensive infrastructure, including its large and deep port and 3,000m runway,” Mr Ian Storey, a South China Sea expert at Singapore’s Iseas Yusof Ishak Institute, told Reuters.

“The timing is interesting, too. It is a show of US determination ahead of President Obama’s trip to Vietnam later this month,” added Mr Storey.

Speaking in Hanoi ahead of Mr Obama’s visit this month, Mr Daniel Russel, the Assistant Secretary of State for East Asia and the Pacific, said freedom-of-navigation operations were important for smaller nations.

“If the world’s most powerful navy cannot sail where international law permits, then what happens to the ships of navies of smaller countries?” Mr Russel told reporters before news of the operation was made public.

“If our warships can’t exercise legitimate rights under international law at sea, then what about the fishermen, what about the cargo ships? How will they prevent themselves from being blocked by stronger nations?” AGENCIES