A US warship sailed within 12 nautical miles of a disputed island in the South China Sea Saturday to assert freedom of navigation, drawing a protest from Beijing, officials said.
"We conducted a freedom of navigation operation in the South China Sea earlier tonight," Pentagon spokesman Jeff Davis said in a statement.
Davis said the guided missile destroyer USS Curtis Wilbur made the "innocent passage" off Triton Island in the Paracel island chain, which is claimed by China, Taiwan and Vietnam.
No Chinese navy ships were in the area at the time the US destroyer sailed within 12 nautical miles of the tiny 1.2 square kilometer island, he said.
The operation was conducted "to challenge excessive maritime claims of parties that claim the Paracel Islands," Davis said.
While the United States takes no position on the various claims to the island, it does not recognize any claimant's right to its territorial waters.
Beijing quickly responded, saying the move violated Chinese law and urging the United States to maintain peace.
"The US warship, in violation of relevant Chinese laws, entered China's territorial waters without authorisation. The Chinese side has taken lawful surveillance, vocal warnings and other related measures," China's foreign ministry spokeswoman Hua Chunying said in a statement.
"We urge the US side to respect (and) abide by relevant Chinese laws, to do more things conducive to Sino-US mutual trust and regional peace and stability," the statement said.
China refers to the islands as the Xisha archipelago.
China claims virtually all of the South China Sea, while the Philippines, Vietnam, Malaysia, Brunei and Taiwan also have partial claims.
China has asserted its claims by rapidly building artificial islands in another South China Sea island chain, the Spratlys, raising tensions in the region.
Port facilities, air strips and military buildings have gone up on the built-out islands, prompting US warnings that it would assert its rights to "fly, sail and operate wherever international law allows."
In October, the US Navy sent a guided missile destroyer within 12 nautical miles of the Spratlys to press home the point.
Davis said Saturday's mission was conducted with no notice given to any of the countries laying claim to the Paracels.
"This operation challenged attempts by the three claimants -- China, Taiwan and Vietnam -- to restrict navigation rights and freedoms around the features they claim by policies that require prior permission or notification of transit within territorial seas," Davis said.
"The excessive claims regarding Triton Island are inconsistent with international law as reflected in the Law of the Sea Convention."
Davis added that while the United States takes no position on sovereignty claims in the South China Sea, "we do take a strong position on protecting the rights, freedoms and lawful uses of the sea and airspace guaranteed to all countries. All maritime claims must comply with international law."