Former UN chief Kofi Annan has brought together Kenya's political rivals in an effort to bring an end to the post-election crisis.The fatal shooting of opposition politician Melitus Were outside his home stoked the violence on Tuesday, with about a dozen people killed - bringing the death toll to more than 850 since President Mwai Kibaki's disputed December 27 election.Post-election protests have degenerated into cycles of killing between tribes who have never reconciled divisions over land, wealth and power left by British colonial rule and exacerbated by politicians in 44 years of independence.The crisis has cost Kenya its reputation as a peaceful country in a turbulent region, and dented its previously flourishing economy - east Africa's largest.Mr Annan, bringing together President Kibaki and opposition leader Raila Odinga to launch formal mediation, said he was confident the "immediate political issues" could be resolved within a month and the broader issues underlying the crisis within a year."To the leaders gathered here today I say that the people want you to take charge of the situation and do whatever possible to halt the downward spiral that is threatening this beautiful and prosperous country," Mr Annan said.Mr Kibaki added: "We stand here during a defining moment, when we must all make the decision that we must regain the dignity of our nation and restore the stability we have enjoyed since independence."Meanwhile Mr Odinga, who says Mr Kibaki stole the vote, said the most urgent issue was addressing "the deeply flawed results of the presidential elections"."This mediation process must show our people that peace, justice and security are around the corner," he said, stressing that the talks were between his Orange Democratic Movement (ODM) party and Mr Kibaki's party, not his government," he said.The political leaders blame each other for the violence, which has driven more than 250,000 people from their homes.Western donors have urged both sides to take the talks seriously or risk losing development aid.© Independent Television News Limited 2008. All rights reserved.