A US Navy ship had an "unsafe" interaction with a Chinese warship Sunday while the US vessel was conducting a freedom of navigation operation near the disputed Spratly Islands in the South China Sea, causing the US ship to manoeuvre "to prevent a collision," according to US defence officials.

“A (People's Republic of China) Luyang destroyer approached USS Decatur in an unsafe and unprofessional manoeuvre in the vicinity of Gaven Reef in the South China Sea,” Capt. Charles Brown, a spokesman for US Pacific Fleet, told CNN in a statement confirming the incident.

Brown said the Chinese warship “conducted a series of increasingly aggressive manoeuvres accompanied by warnings for the Decatur to depart the area.”

He added that the Chinese destroyer “approached within 45 yards” of the front of the US ship, adding that the Decatur ” manoeuvred to prevent a collision.”

“Our forces will continue to fly, sail and operate anywhere international law allows,” he said.

The close encounter would give the ship's captains just seconds to react to any course change, said Carl Schuster, a former US Navy captain who spent 12 years at sea.

“This was very dangerous. Captains get very nervous when ships get closer than 1,000 yards,” said Schuster, now a Hawaii Pacific University professor.

This incident comes amid heightened US-China tensions over a broad range of issues. Chinese ships often shadow US vessels during freedom of navigation operations but those interactions are usually considered safe.

CNN reported Sunday the USS Decatur sailed within 12 nautical miles of Gaven and Johnson reefs in the Spratly Islands as part of what the US Navy calls freedom of navigation operations, which are meant to enforce the right of free passage in international waters.

While the US Navy conducts such freedom of navigation operations all over the world, China is particularly sensitive about the operations when they come near areas where the Chinese government has built islands and established military facilities on disputed maritime features.

“The US has been repeatedly sending warships to the islands and the adjacent waters in the South China Sea, which has seriously threatened China's sovereignty and safety,” Chinese Defense Ministry spokesman Wu Qian said Tuesday.

“The Chinese military will resolutely perform its defence duties and continue to take all necessary measures to safeguard our sovereignty and the regional peace and stability,” Wu said.

Schuster said China seems to be adopting “a more aggressive response policy” to US ships, emboldened in part by last year's collisions between US destroyers and merchant ships in the Asia-Pacific.