A March 16 satellite image from the CSIS Asia Maritime Transparency Initiative shows one of China's artificial islands in the South China Sea. CSIS Asia Maritime Transparency Initiative/DigitalGlobe hide caption

A March 16 satellite image from the CSIS Asia Maritime Transparency Initiative shows one of China's artificial islands in the South China Sea.

It's called Mischief Reef, appropriately enough, and China is hard at work there, building islands, dredging sand and piling it on top of partly-submerged coral reefs.

The idea is for China to stake an even bigger claim to hotly-contested territory in the South China Sea, which is an area also claimed by the Philippines and Vietnam.

President Obama expressed concern Thursday about China "using its sheer size and muscle to force countries into subordinate positions."

The scale of China's construction in the Spratly Islands is clear in new satellite images released this week. NPR's Melissa Block speaks with Mira Rapp-Hooper, director of the Asia Maritime Transparency Initiative at the Center for Strategic and International Studies the think tank that released the photos about the international response to the island construction.

"It's worth noting that several other claimants in the Spratly Islands have undertaken land reclamation and construction activities in the area before," Rapp-Hooper says. "But the thing that is so startling about China's work is the fact that, this time last year, none of it was occurring."

Use the audio player above to hear the full interview.

MELISSA BLOCK, HOST:

It's called Mischief Reef of all things, and China is hard at work there building islands, dredging sand and piling it on top of partly submerged coral reefs. The idea is to stake an even bigger claim to hotly contested territory in the South China Sea. It's an area also claimed by the Philippines and Vietnam.

More here:

'Great Wall Of Sand': China Builds Islands In Contested Waters