Are those high tech anti-riot devices used in foreign embassies? If not-why aren't they? and could they have prevented some of the deaths that have occured?

No deaths occurred at any embassies as far as I know.

Four American diplomats were killed in a consulate in Benghazi, Libya. A consulate is different than an embassy. An embassy is a fortified compound in a national capital that is legally American (or whoever’s) soil. A consulate could just be some dude’s house with no security.

Also, the violence at the Benghazi consulate wasn’t a mob riot, it appears to have been a planned terrorist attack. They were armed with guns and RPG’s and used military tactics.

As far as the less-lethal weapon you are describing, are you talking about the Active Denial System, aka the “heat ray”? I think it’s pretty controversial and, at minimum, still has some kinks that need to be worked out. And in any case I’m guessing it would be of limited use against the heavily armed attackers at Benghazi.

@Qingu Thanks for the correction, I misunderstood some things about the whole situation. Yeah that’s the thing I was thinking of. I just found This video of it, I seems to me it could be a useful addition to foreign embassies….if all the kinks were worked out.

Generally, the local police force in the city of the Embassy provides most of the protection for the embassy. It costs Oslo loads of money to ‘host’ the US embassy right down town, across the road from the park where the palace is. Our royal family’s palace is less fenced and guarded.

As an aside, hubby and I with little man were in Oslo at the end of July. Large sections of the city had to be closed off because the US Embassy called the local police to report a suspicious bag left under a car across the road from them. Loads of Oslo police and the local bomb specialists came out, with sniffer dogs, the whole nine-yards. A few hours later, the Embassy calls the police back and tells them, ‘Oh.. we forgot. That is our bag, because we have a scheduled security drill/exercise that we are meant to be doing.’ I would send them a bill.

I think @Qingu is correct that the heat-ray weapon would not be very effective in a crowd situation. The people can just move away from the beam and probably can put up a shield of some sort (tin-foil suit?) for an assault.
The really,really loud deafening weapon has the downside that it will get your staff too if they aren’t ALL equipped and trained to use ear protection. And a crowd can’t hear your announcements, requests and warnings, on a bullhorn etc., if they can’t hear anything.

Could mount repeating taser weapons on the perimeter fence. You’d have a pile of twitching zombies at the gate in no time. <= I’m not advocating that, just sayin’.