At least eight people have been killed in the latest tribal violence in Kenya's Tana Delta, police and local officials say.

Wednesday's fighting took place in the village of Nduru, near the country's southeastern coast.

Fighting over land and water between the Pokomo and Orma communities in the area has been ongoing for the past few months.

The local county commissioner told Al Jazeera the latest violence was sparked by a Pokomo attack on an Orma village. Five Orma community members were killed, in addition to two of the raiders, he said.

A senior police officer told the AFP news agency that nine other people were wounded and had been taken to hospital.

Kenya's Red Cross confirmed there had been "fresh attacks" overnight at Nduru, adding that three of the critically wounded had been shifted to Malindi hospital by their medical teams. One of those people later succumbed to their wounds.

More than forty people were killed in the fighting between the Pokomo, mainly farmers, and the Orma, who are mainly pastoralists, in December. The violence has been attributed to disputes over water and grazing rights.

The police officer said those killed included members of both tribes, taking the number of those killed since the clashes began last year to more than 140.

Mwai Kibaki, the country's president, has ordered a judicial commission to review options on how to stop the violence.

The repeated outbreaks of violence have raised concerns over security and a lack of police capacity in volatile areas ahead of elections due on March 4.

Elections five years ago descended into deadly post-poll killings that shattered Kenya's image as a beacon of regional stability.

The upcoming elections are for the presidency and parliament, as well as for regional gubernatorial posts and local councils.