The first day of high-level talks between China and Vietnam over maritime disputes ended with no progress.
The Vietnamese side made no statement after talks in Hanoi between Beijing's top diplomat Yang Jiechi and Vietnamese Foreign Minister Pham Binh Minh.
However, in a regular media briefing China's foreign ministry accused Vietnam of "hyping up" the issue.
The talks are the first since the territorial disputes sparked anti-China riots across Vietnam last month.
The riots and attacks on factories left several people dead. Many of the factories were in fact Taiwanese owned.
The riots were prompted by China moving an oil rig to a spot off the Paracel Islands in waters claimed by both countries.
China's foreign affairs ministry spokesman Hua Chunying gave some details of the talks during a media briefing in Beijing.
She said Mr Yang had told hosts that the presence of the rig was "completely legal".
Ms Hua said Vietnam was told to "stop its interference and harassment, stop hyping up the issue and stop whipping up disagreement to create new disputes".
The talks are due to end on Thursday.
Since China moved the rig, boats from both countries have been squaring off in the surrounding waters.
A Vietnamese boat sank after it collided with a Chinese ship in late May.
Vietnamese media reported on Wednesday that China had sent more ships and a helicopter to the rig.
China has said the rig will remain in its present location until August.
Both countries have also taken the dispute to the United Nations, and have submitted dossiers on their claims to UN Secretary General Ban Ki-moon.
Beijing had accused Vietnam of "provocations" in the South China Sea, claiming its ships had been rammed more than 1,400 times by Vietnamese vessels.
Beijing has also in recent weeks called Vietnam's claims to the Paracel Islands "absurd and laughable".
But China is also going ahead with its own plans to boost its presence in the disputed area.
Over the weekend Beijing announced it will build a school in the Paracel Islands.