We have had a lot of Russian government posts (Putinbots) here who've been comically easy to detect. I used to let them through just for amusement but they started to get so common that they got spam-blocked. It's odd because it's hardly as if Russia is short of internet-aware people, but I guess they don't want to work for state propaganda.
Based on other experience I don't think other states maintain active posting campaigns. It's a bad way of doing it, anyway: what you want to do is encourage a situation where you get real people doing it for you, feeding them talking points and targets. The Republicans in the Bush years were absolute masters at this, but they've lost control of the machine now.