More than 10 people were killed on Saturday in fighting in the town of Moyale in northern Kenya where troops have been sent to stop a week of fighting between rival ethnic groups that has sent thousands fleeing into Ethiopia, residents said.

Rural communities in northern Kenya have long clashed over the control of valuable grazing land, but the fighting in the town of Moyale has marked an escalation in tension.

Residents say politicians in the region, some 800 km (500 miles) from the capital Nairobi, are using clan militia to jostle for power in new local administrations that have been formed since a March 4 election, and to settle old scores.

More than 20,000 people have fled into Ethiopia, residents and a Kenya Red Cross worker have said.

The government sent an unspecified number of troops from the Kenya Defence Forces to Marsabit, Samburu, Pokot and Turkana counties on Friday to restore peace.

The arid northern region of Kenya is also awash with guns due to its proximity to unstable neighbours such as Somalia, where al Qaeda-linked militants have been fighting to topple the government, and Ethiopia, where rebel fighters have made sporadic incursions into Kenya.

The fighting in Moyale, in Marsabit near the border with Ethiopia, is between rival ethnic groups - Borana on one side and an alliance of Gabra and Burji on the other, battling with guns and mortars.

Local people said more than 10 people were killed on Saturday and that had brought the toll in the town to more than 30 in the past week.

Officials and aid workers in Marsabit county said several houses were burnt down in the town.

"We are yet to assess the number of people killed and those displaced but I am confident the situation is about to be contained," said Issiah Nakoru, Marsabit county commissioner.

Tom Omolo, Kenya Red Cross regional disaster coordinator, told Reuters his staff were unable to reach the areas where there was fighting.

"The whole area is a battlefield, we cannot send our team to help those people injured, offer rescue or assistance, neither can we establish how many people have been killed or injured but we can still hear heavy gun shots," he said.

Tit-for-tat clashes between ethnic groups have also been reported this month in the northwestern Turkana region, an area where explorer Tullow Oil has discovered oil deposits. More than 10 people have been killed in those clashes, and thousands displaced.

Although Tullow's operations have not been affected by the fighting, the oil company was forced to temporarily halt drilling for two weeks in October after local residents stormed their drilling sites demanding more jobs and benefits.