Washington is refusing, though, to take a stand on the location of a Chinese oil rig that Vietnam says is in its territorial waters.
Vietnam says this video shows China's coast guard ramming a Vietnamese fishing vessel last month near a Chinese oil rig in disputed South China Sea waters.
Chinese Foreign Ministry Spokesman Hong Lei said that is not what happened.
"In the relevant seas, China's ships were on the defensive and Vietnam's ships were on the offensive.
Vietnam says it wants the Obama administration to do more to help stop Beijing.
Vietnamese Foreign Ministry Spokesman Le Hai Binh said, "We would like the U.S. to continue to have a stronger voice, as well as more practical and constructive actions to contribute to the peace, stability, security and safety of seas in the region and to solve regional disputes by international law."
Staying on sideline
Washington says it will not take a stand, however, on Hanoi's claim the oil rig is in Vietnamese waters. U.S. State Department Spokeswoman Jen Psaki said, "We encourage the sides to maintain dialogue with each other, but we are not going to weigh in on speculation about their location and what it means."
American Enterprise Institute analyst Michael Auslin said that puts the Obama administration at a disadvantage.
"When the administration goes so far as to say that it is not going to determine whether or not these waters are in the common definition of the exclusive economic zone of Vietnam, you have taken a very great step toward abdicating any input that you can have into this situation," he said.
Auslin said that will be seen by China and U.S. allies as a clear sign Washington will use any excuse to not get involved.
"At least you can lay the groundwork and say, 'Yes, this is clearly in Vietnamese waters. We still believe it is up to Vietnam and China to solve.' But that does not mean that we should not accept what is pretty much a reality and something that we ourselves observe in every other waters all around the world," said Auslin.
American University Professor Hillary Mann Leverett said it is undermining the so-called U.S. pivot of military and diplomatic resources to Asia.
"That is what China wants to show to Vietnam: 'You are under the biggest stress that you have been under, and the one country that could come and help you out is not going to do it. You need to make amends with China.' That is I think very much part of the strategy and why we will continue to see more," said Mann Leverett.
China's foreign ministry says it wants good relations with Vietnam, but it also says "there are principles that China cannot abandon" in the face of what it calls Vietnam's "provocative actions."