Nairobi, Kenya (CNN) -- More than 30 people were killed Monday in southeastern Kenya in the latest outbreak of tribal violence.
A mob of more than 300 people descended on the village of Kilelengwani in the remote Tana Delta on Monday, many of them armed with spears and machetes, the Kenya Red Cross said.
Thirty-three men, women and children were killed, including seven police officers who had been deployed to the area as a buffer between warring tribes.
The massacre comes just days after nearly a dozen people were killed in the same region in what appears to be continued tit-for-tat violence that erupted last month.
The violence is blamed on the Pokomo and Orma tribes prevalent in the region. The Pokomo are largely settled farmers, and the Orma are traditionally pastoralists, tending cattle and goat herds.
There has been long-running tension between the two groups over grazing rights and water sources, but it boiled over last month when the Pokomo attacked an Orma village after an apparent land dispute.
More than 50 people were killed in that attack, mostly women and children.
The revenge attacks are the worst violence in Kenya since more than a thousand people were killed and hundreds of thousands were left homeless after a disputed election in late 2007.
Kenya's security forces have been heavily criticized for being unable to quell the escalating violence along the Tana River.
Samuel Kilele, the police commissioner of the coast, said hundreds of police were in the area, but rugged terrain and poor infrastructure made it hard to get there. He said four local administrators were being fired for their lack of a response.
But in a move indicating the seriousness of the situation, he said the Kenyan military could be brought in to bring security to the region.
"If the situation proves more volatile, then the deployment of the army will be inevitable," Kilele said.