Exclusive: China warns U.S. surveillance plane
Above the South China Sea (CNN)The Chinese navy issued warnings eight times as a U.S. surveillance plane on Wednesday swooped over islands that Beijing is using to extend its zone of influence. The series of man-made islands and the massive Chinese military build-up on them have alarmed the Pentagon, which is carrying out the surveillance flights in order to make clear the U.S. does not recognize China's territorial claims. The militarized islands have also alarmed America's regional allies.
A CNN team was given exclusive access to join in the surveillance flights over the contested waters, which the Pentagon allowed for the first time in order to raise awareness about the challenge posed by the islands and the growing U.S. response. CNN was aboard the P8-A Poseidon, America's most advanced surveillance and submarine-hunting aircraft, and quickly learned that the Chinese are themselves displeased by the U.S. pushback.
"This is the Chinese navy ... This is the Chinese navy ... Please go away ... to avoid misunderstanding," a voice in English crackled through the radio of the aircraft in which CNN was present.
Exclusive: China warns U.S. surveillance plane - CNNPolitics.com
The spratly islands are claimed by at least 5 nations, China is clearly committed exerting its influence in the region. IIRC there are large oil deposits nearby.
I also think they know Obama is a weak POTUS, and that this is the time to establish a presence in the region.