NAIROBI (AFP) -- A scorching drought that threatens millions across east Africa may spark major tribal clashes in Kenya as competition for water and pasture turns violent, a prominent global charity warned Monday.

"The escalating food crisis in Kenya is threatening to plunge the affected region into a level of conflict that hasn't been seen for almost a decade," Oxfam International said.

"The drought and food crisis in Kenya is so severe that it is leading to nomadic cattle herders fighting over resources," the British-based group said.

Clashes between nomadic pastoralists in Kenya's drought-afflicted north and raids from livestock-dependent herdsmen in southern Sudan and Ethiopia have already occurred and will intensify unless aid is urgently boosted, it said. "The knock-on impact of the (food) crisis risks sparking conflict on a scale that Kenya hasn't seen for almost a decade," Oxfam said.

"We now have a very small window in which to stop this crisis turning into a catastrophe."

"The implications of failing to step up the aid effort now will not just be starvation, it could also bring large scale conflict to the region," he said.

"It's not too late to avert the worst of this, but it soon will be."

Already last month, nomads from neighboring Ethiopia and Sudan staged a raid in northwestern Kenya, killing at least 38 people, and violence involving Kenya's Turkana and Uganda's Karamajong tribes has also been reported.

In northeastern Kenya, where at least 40 people have died of drought-related malnutrition and associated illness since December, hundreds of thousands of livestock have perished and theft of goats and cattle have soared, Oxfam said.

Inter-clan violence in the area is not uncommon but the drought has raised the stakes and the prevalence of automatic weapons in the hands of tribal warriors who once used spears and other crude arms has made raids more lethal.