China has defended its construction of artificial islands in a disputed area of the South China Sea, saying it is needed to safeguard its sovereignty.
Its statement came after US criticism and the online publication of pictures showing the build-up on Mischief Reef.
In recent years, China has been locked in a dispute with several neighbours over claims in the sea.
Other countries have accused China of illegally entrenching its presence through reclamation.
The Center for Strategic and International Studies’ website published before-and-after satellite pictures of the construction, showing man-made islands with runways and harbours, and Chinese vessels dredging sand on to the reef, located among the Spratly islands.
The photos came as several US officials publicly voiced concern about China’s reclamation works in the sea. The latest was Defence Secretary Ashton Carter, who said on Wednesday that China’s actions “seriously increase tensions” in the region.
China gave one of its most detailed comments on the issue on Thursday at a foreign ministry daily press briefing.
Spokesman Hua Chunying said (transcript in Chinese) that China had “indisputable rights” to the Spratly islands, and that it was only “protecting the country’s national sovereignty and maritime rights.”
She said China was “committed to taking the path of peace” and prioritised stability in the South China Sea. Without naming names, she also said that a certain country was practising “double standards” by not voicing concerns on other countries’ “illegal occupation” of China’s maritime territory.
She added that the construction was to serve troops protecting the area and civilian activity such as search and rescue operations, scientific research and commercial fishing.
The structures seen in the satellite photos were to shelter boats, provide rescue assistance, measure ocean conditions, and assist the fishing industry “for China as well as neighbouring countries”.
“The structures… do not affect, nor are they targeted at, any particular country,” she said, adding that China would “continue to strengthen” its activities in the area.
Besides Mr Carter, several US navy officials have weighed in on China’s reclamation.
The commander of the US Pacific fleet, Adm Harry Harris, said in a speech in Australia last week that China was “creating a great wall of sand with dredges and bulldozers”.
He said that efforts in the area had created more than 4 sq km of artificial land mass.
US Navy Lt Cmdr Wilson VornDick wrote in an analysis on the CSIS website: “It appears that China’s building projects are part of an expansive territorial grab or to make China’s disputed Nine-Dash Line claim a reality.”
The Nine-Dash line is a boundary which China uses to demarcate its claims in the South China Sea.
The Philippines, Vietnam, Taiwan, Indonesia, Malaysia and Japan have competing claims in the area.
Tensions have sometimes flared, as when the placement of an oil rig off the coast of Vietnam sparked anti-China riots in the South East Asian country last year.
The Philippines has filed a complaint with UN’s Permanent Court of Arbitration – but China says it will not engage with the case.