KINSHASA, Feb 1 (Reuters) - At least 10 people were killed in clashes between police and opposition supporters in Democratic Republic of Congo's western province of Bas-Congo overnight, United Nations Radio Okapi said on Thursday. The violence took place as members of the Union of the Nation, the opposition coalition of Jean-Pierre Bemba who lost a presidential election to President Joseph Kabila last year, called for protests in Bas-Congo.