One terrorist group HAS claimed responsibility... some Anti-Chinese band
Falun Gong?
Fulan Gong, by itself, would not be able to achieve this - they have major problems with China and China has major problems with them.
I do question China, North Korea and Russia; a different and brand new "axis of evil".
Just sayin'............
Comes at a convenient time what with Crimea/Russia. If Russia is to take on Crimea, I think Putin knows he can roll Obama with Obama's "flexibility.