Talks to end weeks of postelection violence in Kenya resumed Tuesday on thorny political issues, a day after rivals agreed on humanitarian aid and a leading mediator left the team because of government opposition. The fighting has killed more than 1,000 people and made 300,000 homeless since the December 27 presidential election, which foreign and local observers say was rigged. Protests have deteriorated into ethnic clashes, with much of the anger aimed at President Mwai Kibaki's Kikuyu tribe, long resented for dominating politics and the economy. Former UN Secretary-General Kofi Annan, who last month brought together Kibaki and his chief rival, Raila Odinga, warned that Tuesday's agenda would be tough. "The crisis arising out of the December 2007 elections, that is going to take hard negotiations, understandably give and take," he said. On Friday, the two sides agreed to take immediate action to end the violence, and said they would complete talks within 15 days on measures to resolve the political crisis. Annan said it would take up to a year to solve the deeper problems. Although both sides have expressed faith in the Annan-led process, chief mediator Cyril Ramaphosa - Annan's choice - withdrew on Monday because of objections by Kibaki's government and ruling party. Ramaphosa, a South African businessman who had played a leading role in talks to end apartheid in his own country, said he could not function as mediator "without the complete confidence" of both parties. Annan said he would continue to seek a new mediator. On Monday, the two sides signed a two-page agreement on immediate measures, including helping people return to their homes safely and providing food and shelter for the displaced. They also welcomed a UN human rights team to investigate the violence, and agreed on Annan's plan for the establishment of a truth and reconciliation commission with local and international jurists. Streets appeared calm Tuesday in western Kenya, scene of some of the worst bloodshed, after more than a week of clashes. At least seven people were killed in battles between Kisii and Kalenjin communities in a region 250 kilometers west of the capital, Nairobi. Hundreds of youths - armed with bows and arrows and machetes - have fought there for nine days, forcing 2,000 people to flee their homes. South African Archbishop Desmond Tutu urged Kenyans not to arm themselves. "If you are asked to take up arms, reject that call," Tutu said Monday in an interview with the British Broadcasting Corp. "By putting down your arms you will demonstrate the character that God gave to each of you, and to which I now appeal. It is in your power to stop the violence - if you act as one," he added. The Kenya Red Cross on Monday put the official toll at 1,000 killed, thousands injured and 304,000 homeless.