Authorities in Kenya say the death toll in tribal clashes in the southeastern Tana River region has risen to 45.

A local police official says the clashes started when a group of ethnic Pokomo, armed with spears and firearms, raided a village belonging to the Orma people before dawn on Friday.

The Kenya Red Cross says 13 children and six women were among those killed in the attack on Kipao village, and at least 45 houses were set on fire.

Dozens of people were arrested in the aftermath of the attacks.

Police say they have identified where the attackers came from and 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.

In August and September, more than 100 people were killed during clashes between Pokomo farmers, and the Orma, who are mainly herders.

The United Nations says some of the killings may be related to increased tensions surrounding next year's general elections.

More than 1,100 people were killed in violent attacks after Kenya's 2007 election.