Beijing's ambassador to the United States made a blunt rebuke Tuesday of an international tribunal ruling that rendered its claims in the South China Sea invalid.

China must accept a verdict declaring its South China Sea claims are invalid, Australia said Wednesday, and needs to halt its artificial island building in the disputed waters.

European Union President Donald Tusk on Tuesday cautioned China to respect the international system, as the world's second-largest economy finds itself locked in disagreements over maritime law and global trade practices.

A United Nations-backed tribunal on Tuesday issued a damning ruling against China on its long-running dispute with the Philippines in the South China Sea.

Beijing "does not accept and does not recognise" the ruling by a UN-backed tribunal on its dispute with the Philippines over the South China Sea, the foreign ministry said Tuesday.

An international tribunal ruled on Tuesday against China's claims it had "historical rights" in the South China Sea in a bitter dispute that risks further stoking regional tensions.

A UN-backed tribunal is on Tuesday expected to deliver its verdict on a Philippine challenge over Chinese-occupied territory in the South China Sea.

Beijing braced Tuesday for an international tribunal's ruling on the South China Sea, where it has expansive territorial claims, with all eyes watching for the Asian giant's reaction on the ground or in the water.

Vietnam has accused the Chinese coastguard of sinking a fishing boat near a disputed island chain, authorities said Tuesday, ahead of key UN-backed ruling on claims in the flashpoint South China Sea.

The Philippine embassy in China has warned its citizens to beware of personal "threats" and avoid political debates ahead of a tribunal ruling Tuesday over a bitter dispute in the South China Sea.