Secretary of State John Kerry said the United States is "deeply concerned" that China has placed an oil rig in an area of the South China Sea also claimed by Vietnam.
The comments come as Beijing's army chief begins a trip to the U.S., as part of efforts to increase U.S.-China military cooperation and reduce maritime tensions.
Chinese and Vietnamese ships have rammed into each other and exchanged water cannon fire on several occasions since Beijing set up the state-run oil rig last month.
State Department spokeswoman Jen Psaki said Kerry told Chinese Foreign Minister Wang Yi in a phone call the move was "provocative" and "aggressive."
In response, China's Foreign Ministry said Wang urged Kerry to "speak and act cautiously," saying he should be objective when talking about China.
Analysts say the dispute is likely to be discussed during the U.S. visit of Fang Fenghui, China's chief of the general staff of the People's Liberation Army.
The state-run China Daily newspaper said the trip will also highlight both countries' willingness for closer military cooperation.
Brad Glosserman, executive director of the Hawaii-based Pacific Forum, told VOA it is crucial that U.S.-China military ties improve.
"Given what you have in the South China Sea, and the East China Sea, quite frankly, I think what you have is an opportunity for the two militaries to talk, to try to get some better understanding of each others' intentions, so that the possibility of a miscalculation or an accident at sea is diminished," said Glosserman.
Glosserman said military relations are starting "at a very low base," but he expects visits such as this one will help provide for more substantive exchanges.
Fang's visit comes at the invitation of his American counterpart, Joint Chiefs of Staff Chairman General Martin Dempsey, who visited China in April 2013.
U.S. officials have repeatedly expressed concern about China's increasing aggressiveness in defending its vast maritime claims in the South China Sea.
China claims nearly the entire 2.5-million square kilometer South China Sea. Its claims overlap with that of Vietnam, Brunei, Malaysia and the Philippines.
The U.S. says it does not take sides in the disputes, but says it is interested in upholding the rule of law and ensuring that unilateral steps are not taken.