At the link there is also an article by Bill Gertz:
http://freebeacon.com/border-patrol/
BY: Bill Gertz
April 1, 2013 2:30 pm
China has placed military forces on heightened alert in the northeastern part of the country as tensions mount on the Korean peninsula following recent threats by Pyongyang to attack, U.S. officials said.
Reports from the region reveal the Chinese People’s Liberation Army (PLA) recently increased its military posture in response to the heightened tensions, specifically North Korea’s declaration of a “state of war” and threats to conduct missile attacks against the United States and South Korea.
According to the officials, the PLA has stepped up military mobilization in the border region with North Korea since mid-March, including troop movements and warplane activity.
snip
The Bill Gertz article points out that China is sending conflicting signals by, for example, cutting oil transfers to the Norks but reiterating their decision to defend them.
He points out that China fears mass refugees on the same level as a Norks’ war with the ROKs.