Biden expressed his concern when he met the Chinese People's Liberation Army Chief of General Staff Fang Fenghui at the White House on Thursday. (Agencies)
"The Vice President underscored the United States' serious concern about China's unilateral actions in waters disputed with Vietnam," the White House said.
Biden reaffirmed that while US does not take a position on the competing territorial claims, no nation should take provocative steps to advance claims over disputed areas in a manner that undermines peace and stability in the region, the White House said.
"The Vice President and General Fang also discussed the importance of the US-China relationship in the context of addressing a range of regional and global challenges," it said.
Earlier on Thursday, Nina Hachigian, Nominee to be representative of US to the Association of Southeast Asian Nations (ASEAN), told lawmakers that US has a national interest in the unfettered flow of this commerce and in freedom of navigation and overflight in these waters.
"Half of the tonnage of the world's ship-based cargo passes through the South China Sea," she said during her confirmation hearing.
"We have a deep stake in ensuring that the territorial and maritime disputes in the South China Sea are solved peacefully, without coercion, force or intimidation and in accordance with international law.
"Unfortunately, we have seen lately what appears to be a pattern of unilateral actions by China to advance its territorial and maritime claims, the latest of which is China's introduction of an oil rig into the disputed waters near the Paracel Islands. This is provocative and raises tensions, and it highlights the need for claimants to clarify their claims in accordance with international law," she said.
China, she said, is a major economic player in the region, no question.
"They have strong trading relationship with ASEAN. But we have strong trading relationships with ASEAN as well and we're the largest foreign investor by far," Hachigian added.
Biden expressed his concern when he met the Chinese People's Liberation Army Chief of General Staff Fang Fenghui at the White House on Thursday.