China's decision to place an oil rig in disputed waters in the South China Sea is a provocative act and raises tensions in the region, the White House said on Friday.
"We consider that act provocative and we consider it one that undermines the goal that we share, which is peaceful resolution of these disputes and general stability in the region," White House spokesman Jay Carney said at his regularly scheduled briefing.
"We're very concerned about dangerous conduct and intimidation by government-controlled assets operating in this area," Carney said.
Anti-Chinese violence flared in Vietnam this week after China put an oil rig in an spot claimed by Hanoi. The move is the latest in a series of confrontations between China and neighbors over small islands in the oil-and-gas rich body of water, prompting fears that Beijing has adopted a more assertive approach to territorial disputes after seeing Russia annex Crimea.
The White House statement was the most direct U.S. criticism of China since the placement of the oil rig escalated tensions in the region.
During a trip through Asia in April, Obama provided reassurances to several countries that while the United States wants to see maritime disputes settled through diplomacy, it would live up to its obligation to defend its allies in the region.
"These events highlight the need for the claimants to clarify their claims in accordance with international law and to reach agreement on appropriate behavior and activities in disputed areas," Carney said. He added that while the United States does not take a position in the disputes, it opposes any efforts to settle them by intimidation or coercion.
The Philippines, one of Washington's closest allies in Asia, has said China is reclaiming land on a reef that both countries claim, and is building what appears to be an airstrip on it. It has offered the United States the use of an underdeveloped naval base on a nearby island to ensure U.S. warships can enter the vicinity.
Carney said he disagrees with a statement by China's foreign ministry that it is in fact the U.S. announcement it will pursue a more active role in Asia - the so-called rebalancing - that is stirring tensions by emboldening Vietnam and others to behave more aggressively to territorial standoffs.
(Reporting by Mark Felsenthal, Steve Holland and Jeff Mason; Editing by James Dalgleish and Tom Brown)