BEIJING - China on Saturday opposed US Defense Secretary Ash Carter's remarks that China's island-building activities in the South China Sea are undermining security in the Asia-Pacific region.

"China's construction in the South China Sea is within China's sovereign rights and its activities are lawful, reasonable and justified," Chinese Foreign Ministry spokesperson Hua Chunying said, following Carter's comments on Saturday at the annual Shangri-La Dialogue in Singapore.

Hua urged the United States to keep its promise of a neutral position on the sovereignty issue and to stop harming regional peace and stability.

The South China Sea is not a US concern, so it should act prudently and respect efforts by countries in the region to maintain peace and stability, Hua said.

China's sovereignty, rights and interests in the South China Sea have been consistently upheld by successive Chinese governments and established over a long history, with ample historical and legal basis, Hua said, noting that they need not be strengthened through construction in the islands and reefs.

"China's construction activities on the Nansha islands and reefs are entirely within China's sovereignty. They are lawful, justified and reasonable and do not affect or target any particular country," Hua said.

The construction is aimed at strengthening the function of some islands and reefs by providing services, Hua said, adding that aside from meeting necessary defense needs, it is also geared at serving civilian purposes.

Hua reaffirmed that China firmly upholds its sovereignty and maritime rights and interests, and is opposed to words or actions that encroach on China's sovereignty and legitimate rights and interests or affect regional peace and stability.

China is a big country that shoulders more international responsibilities and obligations, Hua said, noting that the country is conducting construction activities at a pace and with a scale befitting its international responsibilities and obligations in search and rescue, disaster prevention and mitigation, meteorological observation, ecological conservation, navigation safety and fishery services.

There has never been any issue with freedom of navigation in the South China Sea, nor will such an issue arise in the future, Hua said.

Hua said the right to freedom of navigation and the air should not be abused or infringe on the sovereignty, rights and security of littoral states, which are protected by international law.

Rather than affecting freedom of navigation, Hua said, the construction will contribute to joint responses to maritime challenges and safety of navigation in the South China Sea.

According to Hua, China and ASEAN countries have identified a "dual track" approach on the South China Sea, which calls for disputes to be resolved through negotiation and consultation between concerned parties and for China and ASEAN member states to work together to maintain peace and stability.

Hua said progress has been made in consultations on a Code of Conduct in the South China Sea (COC), and the COC is meant to be a set of rules for China and countries in the region rather than rules set by outsiders.