Summary:
At least 28 people have been killed in a series of retaliatory attacks between two tribes in Kenya, officials say.

Full article:
Nairobi, Kenya (CNN) -- Rival tribesmen armed with arrows and machetes clashed at dawn Friday, leaving 32 dead in renewed violence in southeastern Kenya, the Red Cross said. At least 30 more were injured in the clashes between Pokomo and Orma tribes in Tana River district, the Kenya Red Cross said in a statement. Casualties included women and children, it said. Read more: Kenyan DJs fast to promote peace . Deputy police chief, Robert Kitur, said preliminary reports show the attack killed at least 28 people. The number of those injured is still unclear, he said. Pokomo tribesmen initiated the attacks, according to Khadija Kuresha, a human rights activist in the area. Both sides have engaged in retaliatory clashes in recent months. It's unclear what triggered the latest clashes, but the two groups have fought for years over grazing rights, land and water sources. Pokomos are largely farmers while the semi-nomadic Orma tribesmen mostly tend to livestock. The former have accused the latter of grazing cattle on land that does not belong to them. Violence between the two escalated after an August confrontation killed more than 50 people in the same region. Kenya has dispatched hundreds of officers to the area in recent months, but authorities in the east African nation have been criticized for failing to stop the carnage.