Thousands of protesters have clashed with riot police and burned election posters of President Joseph Kabila ahead of a historic poll in the Democratic Republic of Congo. Police fired tear gas at demonstrators who threw molotov cocktails and chunks of masonry. They ripped Kabila's campaign posters from signposts and set fire to banners in the streets of the capital, Kinshasa. The country is tense ahead of Sunday's vote - the first free, multiparty elections for presidential and parliamentary positions for more than 40 years.