(Adds Kufuor comments) By Kwasi Kpodo ACCRA, Jan 11 (Reuters) - Former U.N. Secretary General Kofi Annan on Friday called on Kenya's president and opposition leader to cooperate with African mediators to quickly resolve the political crisis in the East African country. Annan, who said he had a accepted a mission to lead a panel of African personalities to mediate, said he hoped to move as quickly as possible, but gave no time frame. "Political negotiation is not an event, it is a process that can take a very long time, or a short time -- all depends on the cooperation of the leaders," Annan said in Accra after holding talks there with African Union Chairman and Ghanaian President John Kufuor. Kufuor had announced Annan's role in Nairobi on Thursday after his own mediation trip to Kenya failed to broker an immediate reconciliation between Kenyan President Mwai Kibaki and opposition chief Raila Odinga. Around 500 people have been killed in political and ethnic violence in Kenya after a disputed Dec. 27 poll that Odinga says Kibaki rigged to achieve re-election. Annan said he had already begun talking to the other members of the panel -- Graca Machel, wife of former South African President Nelson Mandela, and former Tanzanian President Ben Mkapa -- about setting up a secretariat for the Kenya mediation mission. "I regard it as a great responsibility and we'll take it seriously in order to restore stability and quickly end the humanitarian crisis in that country," Annan added. "We are not going to impose solutions but work together with (Kibaki and Odinga) to arrive at viable and long-lasting solutions to the problem," he said. In his remarks, AU chief Kufuor disputed suggestions that his own trip to Kenya failed to achieve any meaningful results. He said it had succeeded in getting Kibaki and Odinga to agree to end violence, recognise the need for dialogue and accept the idea of working with the panel to be headed by Annan. "I did not go there expecting to use the two days to restore total peace in Kenya. It's not a one-day job. That's impossible," Kufuor said. "You don't conjure a solution of this nature. It might take time and let's leave it to the panel to set its own agenda and time frame." Kufuor said the AU had received offers of help to try to solve the Kenya crisis from the British and U.S. governments, as well as the United Nations. "Even though we had these offers, we did not take them, because we realised the problem was an African problem and must be addressed in that context. We took charge as Africans without any such help," he said. (Editing by Pascal Fletcher)
Opposition leader Raila Odinga arrives for a news conference in Nairobi, January 11, 2008. Kenya's opposition on Friday called three days of nationwide protests next week to put pressure on President ...