At least 48 people have been killed in ethnic clashes in south-eastern Kenya, officials say.
The clashes in Tana River district, Coast Province, took place late on Tuesday between the Orma and Pokomo groups, the region's police chief said.
Most of the dead were women and children, he said. Police have been deployed to the area.
The clash is the worst single incident since violence rocked the country after disputed polls four years ago.
Regional deputy police chief Joseph Kitur told AFP news agency that those killed were either hacked to death with machetes or burned alive when their huts were set alight.
The victims included 31 women, 11 children and six men, he said, describing it as "a very bad incident".
'Revenge attack'
The BBC's Frenny Jowi in the capital, Nairobi, says violence between the two communities is often reported, but not on such a huge scale.
BBC reporter says there is long-standing enmity between the area's pastoralist communities, who get caught up in a cycle of revenge killings over the theft of cattle and grazing and water rights.
In 2001, a series of clashes between the Orma and Pokomo left at least 130 dead in the same region.
The semi-arid region is one of the poorest in Kenya, with very little infrastructure or industry.
The government recently created a ministry to promote development in Kenya's arid and semi-arid areas, but there has been little improvement in peoples' lives, she adds.
Kitur said the attack had been carried out by the Pokomo on the Orma, according to initial investigations.
Danson Mungatana, the lawmaker for the area, said the killings were the latest in a string of attacks and cattle raids and had been taken in retaliation for a previous incident.
"There have been problems simmering for a while," he told AFP.
PHOTO CAPTION
Map of Kenya locating Coast Province
BBC