KUALA LUMPUR – An Australian frigate has joined three US warships in the South China Sea near an area where a Chinese vessel is suspected to be exploring for oil, near waters also claimed by Vietnam and Malaysia, officials said.

The warships arrived this week close to where the Chinese government survey ship Haiyang Dizhi 8 has been operating, which is in turn near where a vessel operated by Malaysia’s Petronas state oil company is conducting exploratory drilling, regional security sources have said.

The US navy said the USS America amphibious assault ship and the USS Bunker Hill, a guided missile cruiser, were operating in the South China Sea.

They were joined by Australia‘s frigate HMAS Parramatta and a third US vessel, the destroyer USS Barry, as part of a joint exercise, theAustralian defence department said.

“During the passage exercises, the ships honed interoperability between Australian and US navies, including replenishment-at-sea, aviation operations, maritime manoeuvres and communications drills,” it said in a statement to Reuters.

USS Bunker Hill moves into position to conduct a joint training firing serial with HMAS Parramatta during a recent transit of the South China Sea, in this April 14, 2020 handout photo. (Photo: Australia Department Of Defence/ Handout via Reuters)

The Haiyang Dizhi 8 was 325 km off the Malaysian coast, within its exclusive economic zone, data from ship-tracking website Marine Traffic showed.

The ship, accompanied by a Chinese coastguard vessel, has been moving in a hash-shaped pattern consistent with a seismic survey for nearly a week, the data showed.

The area is near waters claimed by both Vietnam and Malaysia as well as China.

China claims most of the energy-rich South China Sea, within a U-shaped “nine-dash line” on its maps, which is not recognised by its neighbours.

Petronas and Malaysia’s foreign ministry have not commented on the situation but the United States has called on China to stop its “bullying behaviour” in the South China Sea.

China, however, has denied reports of a standoff, saying the Haiyang Dizhi 8 was conducting normal activities.

A Royal Australian Navy MH-60R Seahawk helicopter takes off from HMAS Parramatta during a South China Sea transit, in this April 14, 2020 handout photo. (Photo: Australia Department Of Defence/ Handout via Reuters)

Last year, Vietnamese vessels spent months shadowing the Haiyang Dizhi 8.

It appeared off Vietnam again last week, within Vietnam’s exclusive economic zone. Vietnam said it was closely monitoring the situation.

The United States has accused China of pushing its presence in the South China Sea while other claimants are pre-occupied with the coronavirus.

At the same time, China has been donating medical aid to Southeast Asian countries to help them tackle the virus, which emerged in central China late last year.

A team of Chinese medical experts arrived this week in Malaysia, which has reported more than 5,400 coronavirus infections.

On Sunday, Vietnam protested after China said it had established two administrative districts on the Paracel and Spratly islands in the disputed waters. China has called Vietnam’s claims illegal.

Reuters