HANOI, Vietnam (AP) — Australia and Vietnam have expressed serious concern over tensions in the disputed South China Sea, where Hanoi says China's gas survey ship has infringed on its territory and has disrupted Vietnam's exploration activities.

Australian Prime Minister Scott Morrison met in Hanoi with his counterpart Nguyen Xuan Phuc and both leaders called for respect of international law and freedom of navigation.

Earlier the United States said it was deeply concerned that China is continuing to interfere with Vietnam's longstanding oil and gas activities in Vietnam's exclusive economic zone. China claims the South China Sea virtually in its entirety.

Beijing has deployed a survey vessel with armed escorts into waters off Vietnam, ignoring Hanoi's calls to leave the area.