Villagers in northern Kenya fear further violence after at least 31 police officers were killed over the weekend, an elder has told the BBC."The situation is very, very tense with heavily armed security personnel patrolling villages," said the religious leader in Samburu County.The officers were ambushed as they attempted to recover stolen cattle.Internal Security Minister Katoo ole Metito vowed to bring those responsible to justice.He told the Standard newspaper the "disaster" was the worst in Kenya's history.But the religious leader, who did not want to be named, said he feared that the security forces could take revenge on the local community."We fear the anger of these security people could fall on innocent civilians, as those who may have killed the policemen are nowhere now," he said.He also said that more bodies still have to be found by officials.Police spokesman Eric Kiraithe said 31 officers were killed in Baragoi, along with three of the attackers.He said that nine injured officers remained in hospital.The local Samburu and Turkana communities often steal cattle from each other, and clash over grazing rights and access to water points.A similar attack, in which 12 people were killed, took place nearby two weeks ago, Kenyan media report.