It's just my opinion, but it sounds like another step in his campaign to give the impression that NK is on the brink of war. I.. don't think anything would actually happen to diplomats there, but he's a bit unhinged so I suppose anything could happen.
The more I read about him, the more I realise no one really knows what he's doing. His father was fairly predictable; he would threaten missile tests and threaten to do more nuclear testing, with the obvious end of wanting sanctions reduced/ more aid/ more oil allowed in to the country. He was more open to bartering and would offer to halt nuclear tests if xyz demands were met.
The son, KJU, has said he will not consider negotiating on NK's nuclear capabilities. So what does he want, then? His father's moves were almost predictable, if unhinged. KJU is very young, 20 years old or so. Is he just trying to impress his generals? The people? Not much is known about him.
The US has flown nuclear-capable B-2 bombers with the South Koreans, as a show of support to them. NK was behind the torpedoing of a South Korean ship a few years back which killed 42 men. They are not impotently blustering, they are practicing what they can get away with. Footage of the US planes has now been used in their propaganda to convince the NK people that they are under imminent attack by the US.
I know some on MN believe the US is keen for another war, but they really can't manage another front now. They've already got Iraq and Afganistan. As I mentioned earlier, when the potential problems with Iran came up a few years back, one of the very first things which came up was that the US military doesn't have the manpower for it. The Iraq war saw soldiers being sent back again for second, third tours of duty, with hardly any break between, more than would normally be expected of them. They also had to draft in National Guard troops which aren't even meant to leave their home state.
Babbling. I know you just asked about the embassies. I believe that is just part of the act. I'm just not sure what the end of the act is meant to bring. Literally no one wants this to escalate. Even Castro has warned KJU to 'consider the impact' of nuclear war. At this point, it's a waiting game. The US and South Koreans need to be very careful to not do.. anything, basically.
I still don't think anything is going to happen, but I'll be damned if I have any idea what he wants. He can't expect to get anything without giving in on the nuclear issue, and he's said he won't. I hope he isn't actually insane.