Taken between January 2012 and March 2015, the pictures show how much additional sand has been dumped on the edges of the reefs.
Diplomats believe the ultimate purpose is to create structures that can serve as viable forward operating bases for Chinese military manoeuvres during future military spats.
The Chinese efforts to create what the Pentagon has dubbed “facts on the water” were criticised last week by Admiral Harry Harris Junior.
America’s top navy official in the Pacific, who described it as a “provocative” attempt to build a “Great Wall of Sand”. While Beijing insists that the Spratly islands are rightfully China’s, America and other Western nations have accused Beijing of pursuing a “might is right” policy on the matter.
New photographs have revealed the extent to which China is building artificial islands in South China Sea in a bid to bolster its territorial dispute with its neighbours.
Taken by satellite over a period of several weeks, the images show how a cluster of Chinese dredging vessels are turning a half-submerged reef into “land” by dumping vast amounts of white sand on it. The extra land mass - already believed to be around 1.5 square miles - is then concreted over, with buildings constructed on it.
The pictures, taken by DigitalGlobe, a commercial satellite imagery provider, and analysed by the Center for Strategic and International Studies, a Washington research group, show the aptly-named Mischief Reef, which lie west of the disputed Spratly Islands. Their ownership is also claimed by Brunei, Malaysia, the Philippines, Taiwan and Vietnam.