"An island must be naturally formed to generate an entitlement to maritime zones. Artificial islands created through land reclamation, in contrast, are not entitled to any maritime zones like a territorial sea or exclusive economic zone," the official said.
On Tuesday, several media reports emerged saying that US Defense Secretary Ash Carter was considering expanding military patrols around the Spratly Islands.
On Wednesday, China's Foreign Ministry spokeswoman said that Beijing is seeking an explanation from Washington for the recently revealed plans to deploy warships in the waters off the Spratly Islands.
"We have, and will continue to operate consistent with the rights, freedoms, and lawful uses of the sea in the South China Sea," the State Department official concluded.
The islands, thought to hold potentially significant oil and gas reserves, are claimed by China, Taiwan, Malaysia, Brunei, the Philippines and Vietnam.
