Authorities in Kenya say the death toll from new tribal clashes in the southeastern Tana River region has risen to 45.
A local police official says the clashes started before dawn Friday, when a group of ethnic Pokomo, armed with spears and firearms, raided a village belonging to the Orma people.
The Kenya Red Cross says 13 children and six women were among those killed in the attack on Kipao village. At least 45 houses were set on fire.
The White House on Saturday condemned the renewed violence "in the strongest terms." A statement voiced sympathy for families that lost loved ones in the violence and urged the Kenyan government, police and tribal leaders to end the deadly cycle of conflict.
Authorities say dozens of people were arrested in the aftermath of the attacks, and say police are pursuing them.
The two groups have waged a series of deadly attacks and counter-attacks as part of an ongoing dispute over land and water.
Earlier this year, more than 100 people were killed in clashes between Pokomo farmers, and the Orma, who are mainly herders.
More than 1,100 people were killed in violent attacks after Kenya's 2007 election, and the United Nations says some of the new violence may be related to rising tensions ahead of general elections set for March 2013.
Some information for this report was provided by AFP.