A local official called for the military to be sent to the Tana Delta area as the police struggled to defuse tension between the Pokomo and Orma communities.
More than 100 people have been shot, hacked and burnt to death in the last three weeks as the two sides take revenge for the other's killings.
The land clashes and deadly riots in the port city of Mombasa following the killing of a radical Muslim preacher last month have raised the prospect of a surge in unrest along the coast ahead of a presidential election next March.
"We will soon recommend to the government to send military officers down there to help us restore order," Samuel Kilele, the provincial commissioner in Coast province, said.
Mwanaisha Hamisi of the Kenyan Red Cross said the death toll from Monday morning's attack by more than 300 assailants on Kilelengwani village was 38 people.
Settled Pokomo farmers and semi-nomadic Orma pastoralists have clashed intermittently for years over access to grazing, farmland and water. The violence broke out again last month after the Pokomo accused the pastoralists of grazing cattle on their land.
"Many of us believe that there is a political instigation to this violence. This violence always take a high crescendo when the political temperatures start take root," Hassan Omar, a lawyer and former commissioner at the Kenya National Commission for Human Rights, said.
Prime Minister Raila Odinga visited the area after an earlier attack but government efforts have so far failed to ease the tensions.
Cattle rustling and clashes over grazing and farming land are relatively common between communities in arid areas of east Africa and often escalate into revenge attacks.
An influx of weapons across Kenya's borders, in particular from war-ravaged Somalia, have made the situation more violent. – Reuters