Surveillance imagery recently obtained by the Center for Strategic & International Studies (CSIS) shows that in recent years Vietnam has undertaken significant construction in the Spratly Islands, a highly contested area in the South China Sea.

The never-before-published satellite photographs, taken between 2010 and April 30 this year, reveal that Hanoi has been carrying out land reclamation activities on two features in the Spratly archipelago: Sand Cay (title picture) and West London Reef. According to the think tank, Hanoi has added 65,000 square meters to West London Reef and some 21,000 square meters to Sand Cay where it has also developed military facilities.

Zachary Abuza, an independent Southeast Asia security analyst, explains that these are amongst the more than a dozen manned outposts that Vietnam maintains on small islands and features in the Spratlys. These include fairly large islands, including Spratly Island, which has its own airfield, as well as small concrete structures constructed on rocks barely above the surface at high tide, as well as steel-constructed lighthouses and aids to navigation.