Who are the two sides of the hostilities according to the news?

Burma officials and representatives of the Karen National Union have signed an agreement that could end more than six decades of hostilities between the Burmese military and the rebel group. The two sides agreed to a ceasefire after meetings in Pa-an. It marks the first time the ethnic Karen rebels and central government agreed to cease hostilities after 63 years of fighting. But KNU General Secretary Zipporah Sein stressed the truce is just the first step in negotiations on a political settlement. The United States and European Union say Burma must establish peace with the ethnic rebels before economic sanctions against it can be lifted. Daniel Schearf, VOA News, Bangkok.
                                                                VOA 2012-1-13