Reports from Kenya say at least 12 more people have died in violence triggered by last month's disputed re-election of President Mwai Kibaki.

Police and residents in the capital, Nairobi, say four people were beaten and hacked to death with machetes in Mathare slum area Sunday. The fighting involved youths from the Kikuyu tribe of President Kibaki and the Luo tribe of opposition leader Raila Odinga.

Authorities say tribal violence in the Kipkelion area of western Kenya's Rift Valley province has killed at least eight people since Friday.

Election-related violence has killed at least 34 people in all across Kenya since Wednesday, when Mr. Odinga's supporters renewed their protests against what they call the rigging of last month's vote.

Mr. Odinga's Orange Democratic Movement has called for more protests on Thursday.

Former U.N. Secretary-General Kofi Annan is due to arrive in Nairobi Tuesday to try to mediate the crisis. Mr. Odinga has said he will meet with Annan.

About 650 people have died since Mr. Kibaki was declared the winner of Kenya's December 27 election. Foreign and domestic observers have said the vote-counting process was seriously flawed.

Some information for this report was provided by AFP, AP and Reuters.