BEIJING, April 9 -- China reiterated construction and maintenance works on some islands and reefs in the Nansha Islands fall within its sovereignty on Thursday.

China has indisputable sovereignty over the Nansha Islands and their adjacent waters, said Foreign Ministry spokesperson Hua Chunying, noting the construction works were reasonable and lawful, and not directed against any country.

China's purpose is to perfect the functions of those islands and reefs, and improve the working and and living conditions of its personnel stationed on those islands, said Hua at a routine press briefing.

She said the construction and maintenance works will enable China to further safeguard its territorial sovereignty as well as maritime rights and interests.

They will also help China to fulfill its international responsibilities in the areas of maritime search-and-rescue, disaster prevention and mitigation, marine research, meteorological observation, environmental protection, navigation security and fishery production.

Hua reiterated China's adherence to a peaceful development path and defensive national defense policy.

"We are in favor of solving disputes with directly concerned countries through negotiations and working with ASEAN countries to jointly safeguard peace and stability of the South China Sea," she said.

Hua said some countries had taken double standards regarding the construction works of China and other related countries in China's Nansha Islands. She did not name a specific country.

"We hope countries concerned would honor their commitments of not taking sides on the South China Sea issue, and do more to help regional peace and stability," said the spokesperson.

After reclaiming the islands and reefs of Nansha Islands, their functions will become integrated and comprehensive, she said, adding that they will not only serve necessary needs of military defense, but are more for civil demands.

The South China Sea is far from the continent and dotted with shipping lanes and fishing grounds, she said, adding that the area has been strongly affected by the monsoon climate, which cause frequent shipwrecks.

Through the construction and maintenance works China will provide necessary assistance for vessels sailing on the South China Sea, she said.

The services may include shelter, aid in navigation, weather forecasts and fishery assistance, according to Hua.

China's construction works on the islands and reefs have undergone scientific assessment and feasibility studies, and have strict standard and requirement for environmental protection, she said.

"We have taken into consideration issues including the ecological environment and fishery protection, in order not to pose any harm to the eco-system of the South China Sea," said the spokesperson.

China will continue its environmental monitoring and protection efforts in related waters, islands and reefs, she added.