The US has said it plans to return to contested areas of the South China Sea, with a top security official saying there will be "more demonstrations" of freedom of navigation in the region.
US deputy national security adviser Ben Rhodes made the comments on Monday.
An unnamed US official also told Reuters news agency that patrols would take place at least "twice a quarter".
The sailing of a US warship within an area claimed by China last week angered Beijing, which issued a warning.
The guided-missile destroyer USS Lassen breached the 12-nautical mile zone that China claims around the Subi and Mischief reefs in the Spratly archipelago.
'Expect more'Mr Rhodes, speaking at an event organised by media outlet Defense One, said ensuring freedom of navigation in the South China Sea was in the US interest.
The outlet quoted him telling the audience to "expect more demonstrations of that interest".
"We have a responsibility to demonstrate that we're going to be there but fostering peaceful resolutions," he added.
The unnamed official separately told Reuters the US military visits to the region could take place as often as "twice a quarter or a little more than that".
"That's the right amount to make it regular but not a constant poke in the eye. It meets the intent to regularly exercise our rights under international law and remind the Chinese and others about our view," the official said.
China's island factory
Why is the South China Sea contentious?
The US and China's naval commanders spoke by video link last week. China told the US that a minor incident could spark conflict in South China Sea if the US did not stop its "provocative acts".
Tensions have escalated in the resource-rich South China Sea in recent years, where several countries have overlapping maritime claims, as China has steadily expanded and consolidated its presence.
China, which claims a wide swathe of the sea, has been reclaiming land around reefs and constructing airstrips and buildings. The US and other countries have called for the halt of such activities, accusing it of militarisation, but China has insisted that the construction is for civilian purposes.
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