Complex sentence: An uprising commenced in Ulan Bator on 1 July 2008 with a peaceful meeting in protest of the election of 29 June results corrupted (as claimed the opposition political parties) by the Mongolian People's Party (MPRP).
Split into simpler sentences: An uprising commenced in Ulan Bator on 1 July 2008, with a peaceful meeting in protest of the election of 29 June. The results of these elections were (it was claimed by opposition political parties) corrupted by the Mongolian People's Party (MPRP).