China's campaign of island building in the South China Sea might soon quadruple the number of airstrips available to the People's Liberation Army in the highly contested and strategically vital region.
That could be bad news for other regional contenders, especially the US, the Philippines and Vietnam.
The island construction work that is creating vast amounts of new acreage by piling sand on top of coral reefs is now moving into the construction stage, with buildings, harbours and, most importantly, runways appearing in recent months.
China now operates one airfield at Woody Island in the Paracel island chain, and satellite photos show what appears to be work on two, possibly three, additional airstrips on newly built islands in the Spratly archipelago to the east.
The bases could have a "significant impact on the local balance of power" by helping bolster the forward presence of Chinese coast guard and navy forces, said Euan Graham, director of the International Security Program at the Lowy Institute in Sydney, Australia.
As with most South China Sea developments, China has remained opaque about its plans for the island airstrips.
At a recent monthly briefing, Defense Ministry spokesman Wu Qian declined to say how many China planned to build or what their purpose would be, repeating only that all military infrastructure was "purely for defensive purposes."
Beijing claims almost all of the South China Sea and its islands and has created seven new features in the Spratlys since last year that are permanently above water totalling more than 2,000 acres in area, according to satellite photos collected by US government agencies and private groups including the Washington-based Center for Strategic and International Studies.
While China insists its island building works are justified and don't constitute a threat to stability, further militarisation of the region seems assured given China's increasingly robust assertions of its territorial claims.
Those perceptions were reinforced with the deployment in October of advanced J-11BH/BHS fighters of the navy air force to Woody Island that was revealed online in China in October. China's military has declined to comment on the reports.
The island's 2.4-kilometre long runway will soon be eclipsed by one more than 3 kilometres long on the reclaimed island built atop Fiery Cross Reef in the Spratlys, the satellite photos show. Another runway is being built on Subi Reef, with signs of similar work underway on nearby Mischief Reef.
