Countless lives have been saved by the ongoing famine relief efforts in the Horn of Africa, the head of the U.S. Agency for International Development said Wednesday.

USAID administrator Raj Shah said that resources used in interventions to stop the famine spreading in the region have made an impact.

He said the relief efforts have mitigated the slide from drought to famine _ which has killed 29,000 children in Somalia _ in pastoral communities in Ethiopia and Kenya. Shah said the U.S. contribution to relief efforts is so far more than $600 million.

He said some pastoral communities have been able to withstand the drought after their livestock _ their main source of livelihood _ was inoculated against diseases.

"As a result, there are nearly 4.5 million in pastoral communities who are still living in their communities," Shah said. "Even though they are suffering _ it's difficult right now _ they are not on this dangerous trek to (aid) camps seeking food, because many of these efforts have worked in preventing this famine from taking hold in parts of the Horn."

The drought and the famine it has caused in Somalia have affected more than 11.5 million people in the Horn of Africa and created a triangle of hunger where the borders of Ethiopia, Kenya and Somalia meet.

The U.N. last week said food assistance is estimated to have reached about 1.85 million Somalis, nearly half of the people in need in the Horn of Africa nation. Still, the U.N. says, 750,000 Somalis are at risk of death from famine in the next four months in Somalia where tens of thousands have already died. Six areas in southern Somalia have been declared famine zones.

Shah said his visit to the region was partly to encourage the government of Kenya and Ethiopia to make tough reforms in their agricultural sectors to unlock more agricultural growth and food self-sufficiency over time.

"So that when there is a future drought they won't need humanitarian assistance because they have sustainably created a more modern, more productive agricultural food system that reaches even their most vulnerable people," he said.