Australian frigate HMAS Parramatta (file photo courtesy of the Royal Australian Navy�s website)

An Australian frigate has joined three US warships in the disputed South China Sea near an area where a Chinese vessel has been based, raising concerns over an escalation of tensions.

Australia�s HMAS Parramatta frigate joined the USS America, an amphibious assault ship, the USS Bunker Hill, a guided missile cruiser, and the USS Barry, a destroyer, US and Australian military sources said on Wednesday, adding that the ships aimed to take part in a joint military exercise.

During the passage exercises, the ships honed interoperability between Australian and US navies, including replenishment-at-sea, aviation operations, maritime maneuvers and communications drills, Reuters reported, citing unnamed military sources.

The warships arrived this week near the area where the Chinese government survey ship Haiyang Dizhi 8 has been based, possibly conducting exploratory drilling.

The ship is accompanied by a Chinese coastguard vessel.

China reported that the Haiyang Dizhi 8 was conducting normal activities.

Nearby waters are claimed by Malaysia, which has one of its own vessels exploring for oil there.

Malaysia�s Foreign Ministry has not issued any complaints regarding the Chinese surveying.

Vietnam, however, has filed a complaint with the United Nations (UN).

Hanoi has also protested China�s alleged efforts to boost its presence in the disputed area.

China claims most of the energy-rich South China Sea, within a U-shaped nine-dash line on its maps, which is not recognized by its regional neighbors, namely Malaysia and Vietnam.

The South China Sea serves as a gateway to global sea routes, through which about 3.4 trillion dollars of trade passes each year. Vietnam, Taiwan, the Philippines, Malaysia, and Brunei have overlapping claims with China to parts of the sea.

The United States, which sides with Beijing�s rivals in the maritime dispute, routinely sends warships and warplanes to the South China Sea to assert what it calls its right to freedom of navigation, ratcheting up tensions among the regional countries.

SOURCE: PRESS TV