China's army looks like it's getting ready for something big to go down in North Korea

China's military has been increasing the strength and number of its forces along its 880-mile border with North Korea as Pyongyang's military provocations cause the US and its allies to think long and hard about military action against the rogue regime.

A report from The Wall Street Journal says that China has established a new border-defense brigade, implemented 24-hour video surveillance of the border, and constructed bunkers to protect from possible nuclear or chemical attacks.

China conducted a live-fire drill in June and July with helicopter gunships and armored infantry units, including a simulated battle with artillery, tanks, and helicopters, according to The Journal. The nature of these military exercises goes beyond securing a border, and they mimic fighting a nuclear-armed adversary.

While China and North Korea exist on paper as allies, Sim Tack, an expert on North Korea at Stratfor, a geopolitical-analysis firm, previously told Business Insider that China would not likely defend Pyongyang from a US-led attack and instead try to prevent or dissuade the US from taking such a step.

Still, a US-led attack on North Korea remains unlikely. South Korea's new liberal government has sought to pursue engagement with its neighbor, and the US would ultimately need its support for such a campaign. From a purely military point of view, North Korea's artillery and nuclear arms hold too many civilians in Seoul at risk.

In June, Secretary of Defense Jim Mattis described possible conflict with North Korea as "a serious, a catastrophic war, especially for innocent people in some of our allied countries, to include Japan most likely."

Even short of war, China now has reason to view North Korea as a liability.

In response to North Korea's missile tests and military provocations, the US based its powerful Thaad missile-defense battery in South Korea, frightening Chinese military analysts who think the Thaad's powerful radar could one day effectively neuter China's ability to engage in a nuclear exchange with the US.

Beijing, which could play a role in handling a refugee crisis, should the North Korean regime collapse, has now assembled forces sufficient to shape the outcome of any conflict between the West and Pyongyang.

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