On Friday, the US state department said Beijing was risking an escalation in tensions by establishing a garrison on one of the disputed Paracel islands.
The Chinese foreign ministry said the US remarks “disregarded the facts” and “sent a seriously wrong signal”.
China lays claim to parts of the sea, overlapping areas claimed by the Philippines, Vietnam, Taiwan, Brunei and Malaysia.
On Friday, the US state department said it was monitoring the situation in the area closely, adding that China’s establishment of a military garrison on Woody Island runs “counter to collaborative diplomatic efforts to resolve differences and risk further escalating tensions in the region”.
On Saturday, China’s Assistant Foreign Minister Zhang Kunsheng said the US statement “disregarded the facts, confused right with wrong, sent a seriously wrong signal and did not help with efforts by relevant parties to maintain peace and stability in the South China Sea or the Asia Pacific”.
There are thought to be significant oil and gas reserves below parts of the South China Sea subject to ownership disputes.
In recent years, tensions over the issue have increased amid growing assertiveness from China over its maritime claims.