The European Union has urged China to stop interfering in the arbitration process, amid mounting concerns that the country’s “robust” trade policy will not be sustainable.
China has stepped up its military and political activities in the South China Sea, where China claims vast tracts of territory from its neighbours.
The dispute between Beijing and Taipei has also caused tensions with Vietnam, Malaysia and the Philippines.
The EU has also warned that it will impose “more and more sanctions” against China if it continues to ignore its international obligations.
“If China continues to engage in the kind of behaviour which is in breach of its international commitments, we will impose more and more punitive measures,” EU Trade Commissioner Karel De Gucht told a news conference on Monday.
“The consequences are clear: sanctions will be imposed against China, we would be more likely to impose them.”
He said that “it is not possible to continue with a robust trade policy” if China is “continuing to be in a state of total and complete uncertainty”.
De Guyt also called on China to allow the EU to use its “technical expertise” to negotiate trade deals with the bloc.
China, a former colonial power, has been building military bases in the Spratly Islands, which are strategically important for both the US and Japan.
De Guterts comments come after a meeting between President Donald Trump and his Chinese counterpart Xi Jinping.
“We are ready to engage to achieve a successful outcome for the Indo-Pacific region and for all concerned in the region,” Mr Trump said after meeting Mr Xi in Washington on Monday afternoon.
The US-China relationship is at a “very low point”, said De Guzeta, adding that the leaders agreed “on the importance of the region”.
“I think there is a real hope for the region and that is why I have spoken to President Xi.
A senior administration official said the US is prepared to engage China on a range of issues including climate change, cyber security and human rights. “
But there are opportunities to develop and grow the relationship, I think we will be able to do that.”
A senior administration official said the US is prepared to engage China on a range of issues including climate change, cyber security and human rights.
“China is going through a very difficult time right now, and they have a lot of work to do to build trust,” the official said.
DeGuterts remarks came after a number of senior US lawmakers said they were not convinced the US should join the Chinese plan to use an arbitration court to settle disputes between China and the other claimants in the disputed sea.
“I am disappointed by the tone of the President’s meeting with Xi, which is very much about his China policy,” said Senator Lindsey Graham, the chairman of the Senate Armed Services Committee.
“He is talking about China as a rival and China as the only power and not a partner in the world.”
A group of Republican lawmakers led by Senator John McCain have also expressed concern over Mr Trump’s decision to visit China on the sidelines of the G20 summit in Hamburg, Germany.
“There is a strong desire in the Republican Party to continue to promote the benefits of our partnership with China and to help them achieve a stronger relationship with the United States,” Senator McCain said.
But he added that Mr Trump has not been briefed on any of the US’s options in dealing with China.
The official said Mr Trump will meet with Chinese President Xi in New York next week.