The latest report from the General Police Agency Communications center is that over 400 officers and other personnel were injured in the riots. About 90 people from that were also injured enough to receive medical attention. Eleven officers were in serious condition. [source: www.news.mn]
Also according the BBC the riots spread to the Cultural Palace, National Art Gallery, and Opera Theatre.
It appears the damage is more extensive than what I could originally see on television. President Enkhbayar has declared a state of emergency for the next four days within the Baga Toiruu (Little Ring Road) and a curfew of 10pm to 8am. More of the presidential decree at http://www.montsame.mn.