They should attempt simultaneous assassination of the entire regime, leader, generals and all. I don't think you can go in on foot - they've got 1.6 million men in the army. Also, nuking the place, whilst desirable would kill a lot of largely innocent people too.
Basically, they need to forcibly be disarmed - China could probably do that, without a bomb going up (and down), and if they're not at the ICBM stage yet, there's little to worry about in the short term.
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CARPE PECTORIS!!
There is nothing about these perplexing and morally insensitive humans that cannot be solved with the aid of a heavy machine gun.