Violence has continued in Kenya's Tana River area despite a dusk-to-dawn curfew after the deaths of 112 people in weeks of clashes.
Three more people, including police officers, are said to have died in the latest attacks.
They were carried out by hundreds of men with guns, spears and machetes, the Red Cross said.
Two communities with a history of rivalry over access to water and land have been engaged in tit-for-tat raids.
President Mwai Kibaki ordered a curfew to be imposed late on Monday in Tana River County.
But the Red Cross says houses have once more been set on fire, forcing people to flee on Tuesday.
The BBC's Gabriel Gatehouse in Kenya says there is a wider issue than the rivalry between the two groups - competition for resources in a country of deep inequalities.
He says the fear is that, as Kenya approaches elections next March, that competition could lead to more of the widespread violence seen after the last poll in December 2007.
Some 38 people including children and police officers were killed on Monday, after the deaths of more than 50 people last month and another 12 last week.
Police spokesman Eric Kiraithe says 112 people have been killed since the latest round of attacks broke out in late August.
The Orma and Pokomo communities have a long history of tension over access to land and water in this ecologically rich area.
The Pokomo are mostly farmers, while the Orma are semi-nomadic cattle-herders.
The BBC's Anne Mawathe, who visited the area at the weekend, says the long-standing rivalry between the two communities has been made worse by an influx of weapons from neighbouring Somalia.