It doesn't sound like this situation is going to end well. BBC:
The Thai military says security forces plan to surround a protest encampment in Bangkok with armoured vehicles.
A spokesman said that routes into the sprawling encampment would be closed at 1800 (1100 GMT). Protesters would be free to leave but not enter, he said.
The move comes a day after the government announced and then cancelled a plan to cut off water and power supplies to the protesters.
