Millions are in danger of starvation due to a prolonged drought in the Horn of Africa, and Obama regretted that the famine was still not gaining enough attention in the United States.

"We discussed how we can partner together to avert the looming humanitarian crisis in Eastern Africa. I think it hasn't got as much attention here in the United States as it deserves," Obama said.

He added that the famine in East Africa, where nearly half of Somalia's 10 million people are in need of relief assistance, "is going to require an international response and Africa will have to be a partner to make sure that tens of thousands of people don't starve to death."

Obama held talks with four West African leaders Friday, including Ivory Coast's new President Alassane Ouattara.

Benin's President Boni Yayi, President Alpha Conde of Guinea and President Mahamadou Issoufou of Niger were also at the White House meeting.

The Al-Shebab insurgents have expelled several foreign aid groups from regions under their control since 2009 and reiterated recently that the ban was still in force after the United Nations declared famine in two regions they rule.

Shebab spokesman Sheikh Ali Mohamud Rage denied there was famine in the southern Somalia regions of Bakool and Lower Shabelle as declared by the UN, but admitted that there was drought.

In a speech to the rebel radio, Rage said local traders and other residents have been the main providers of help to the drought-hit population and that "God did not make them need an outside enemy or non-Muslims, the people in the country fed them very well."

"We need Muslim people to be aware that the external enemy especially non-Muslims have been thinking of a new strategy.

"The new strategy is to transport them abroad, especially in Christian countries like Ethiopia and Kenya, so that their faith can be destroyed and that they could be staff and soldiers for the Christians," Rage charged.

Thousands of Somalis have fled to neighbouring Ethiopia and Kenya to seek relief from the harsh drought that has affected some 12 million people across the Horn of Africa region.

Somalia is the worst hit country by the drought, with malnutrition rates in some regions reaching 50 percent, according to the UN, while nearly half of its 10 million people are in need of humanitarian aid.

The aid restriction by the hardline rebels, who control much of southern and central Somalia, has been singled out as having worsened the effects of the drought.

However, a handful of foreign aid groups were spared the ban and can operate in the militia-controlled regions but with limited scope.

"For the Shebab it means that if the bulk of aid comes from Somali communities, foreign aid cannot be rejected," according to Support Programme (NSP), an organisation which advises aid groups on the Somalia operation.

But the NSP warned that the authority granted by the Shebab to the few foreign aid groups can suddenly be reversed, so the UN and other relief organisations should be cautious about their public pronouncements.

Whether to accept or reject external help has also deepened traditional divisions between moderate and extremist Shebab elements, a Western observer told AFP.

Hardliners led by Shebab chief Ahmed Abdi Godane reject any kind of foreign aid, while the moderates who have strong clan links are more open to outside help.

After initially appealing in early July for help and pledging to allow aid in -- even from non-Muslims -- the Shebab later clarified that the previous ban on some foreign aid groups was still in place.

"It is possibly an illustration of internal dissension among the (Shebab) leadership," the NSP said.

"The announcement of a famine and the massive media reporting over the subject further raised internal discontent and prompted a rapid response," it added.

Forced to pull out of the Shebab-ruled regions in early 2010, the UN's World Food Programme has been distributing aid in Mogadishu and this week began airlifting supplies to feed malnourished children.

The UN children's fund UNICEF and the International Red Cross have on their part distributed aid to insurgent areas recently.

Battered by a relentless civil war since 1991, the plight of Somalis has often been referred to as the world's worst humanitarian crisis.