Bangkok and East Thailand are beginning to shut down. Four (so far) recent bomb blasts have killed one foreigner and several Thais.
The violence here that began more than three weeks ago with a festival type atmosphere is beginning to devolve into something more serious.
The Red Shirts have dug in in central Bangkok, erecting barriers of tyres, bamboo, and barbed wire. The Grand Hyatt and Intercontinental yesterday closed their doors and evacuated their patrons to safer areas.
A grenade attack on the BTS (sky train) which is the most dependable transport in Bangkok shut it down. I also heard unconfirmed reports that the underground (MRT) was also closed. The attack on the BTS killed at least one foreigner and one Thai, while three other explosions assumed to be grenades have put at least 50 in hospital.
Within Bangkok, the violence is very localized, mainly at Siam Square. It's generally easy to avoid the violence, but transport around Bangkok is becoming increasingly affected.
Outside of Bangkok, most transport remains running, including air. At this stage it looks very unlikely that the international airport will be affected. However, several train routes that are used to transport troops to the capital have also been closed down by the Red Shirts, making transport in the north and east a tad more difficult.
To date there hasn't been any suggestion of problems in Pattaya and south of Bangkok to Koh Samui and Phuket. Local problems in Bangkok are political in nature and unrelated to violence in the south, which tends to be more religious in nature.
Helicopters are flying over head, people a bit nervous. It looks like further violence is likely in Bangkok. I wouldn't characterize it as dangerous (more people die on the roads in Samui), but Bangkok looks a bit inconvenient right now. Phuket, on the other hand, seems ok.