World Food Programme (WFP) officials said the areas of southern Somalia controlled by the al Qaeda-linked al Shabaab, which imposed a ban on food aid in 2010, were among the most dangerous to operate in worldwide.
"There are 2.2 million people yet to be reached. It is the most dangerous environment we are working in in the world. But people are dying. It's not about politics, it's about saving lives now," Josette Sheeran, WFP's executive director, told agency staff and reporters in northeastern Kenya.
The drought gripping the region straddling Somalia, Kenya and Ethiopia is the worst for 20 years and is affecting some 10 million people, the United Nations says. In southern Somalia, 3.7 million people risk starvation.
WFP was among several groups ordered out of rebel-held areas last year who were now preparing to return. A WFP official briefing Sheeran said the agency was considering food drops from aircraft in regions inaccessible by land.
Aid groups also face landmines in the border areas where al Shabaab clashed with Kenyan and Ethiopian forces earlier this year, said Regis Chapman, WFP Somalia's head of programme.
Sheeran visited the pastoralist village of El Adow some 100 km from the Somali border. A Reuters witness said cattle carcasses littered the arid lands surrounding the settlement.
More than a quarter of the children in the area are malnourished and a third of adults receiving food handouts, U.N. data showed.