12am, President Enkhbayar is set to declare a state of emergency for 4 days, and has ordered the military on a stand-by. No further details are available at the moment.
The rioters attacked the MPRP headquarters in a bulldozer and have now taken to Sukhbaatar square. The riots escalated further and the Sukhbaatar police headquarters were attacked just earlier.
Update: State of emergency has been declared in Ulaanbaatar for 4 days. As of midnight, there are still around 500 protesters at Sukhbaatar square (with their bulldozer taken from the Shangri-la construction site). The government has ordered a shutdown of all television channels except for the national TV.
Update: The first 4 floors of the MPRP HQ are ablaze. The building has been evacuated according to news reports. Eagle TV reporters are stuck on the roof (see Thomas Terry's blog, link below).
Design Research for Health: Mongolia has a firsthand account of the riots.
Eagle TV has been covering the riots live, and have received threats from the authorities to stop their coverage. Thomas Terry's blog (of Eagle TV's) has an update on the events surrounding Eagle TV.
Update: The rioters have set fire to Sukhbaatar district HQ & the Registrar's office. The rioters have reached the University of Arts & Culture (SUIS), just behind the city square.