The UN has officially declared two parts of Somalia to be in famine amid the worst drought in east Africa for 60 years.
Mark Bowden, humanitarian co-ordinator for Somalia, said on Wednesday that famine conditions now existed in the Bakool and Lower Shabelle regions of the country.
He warned: "If we don't act now, famine will spread to all eight regions of southern Somalia within two months, due to poor harvests and infectious disease outbreaks.
"We still do not have all the resources for food, clean water, shelter and health services to save the lives of hundreds of thousands of Somalis in desperate need."
He added that the lack of resources is alarming. "Every day of delay in assistance is literally a matter of life or death for children and their families in the famine-affected areas."
UN humanitarian agencies have welcomed the recent statement by al-Shabaab, Islamist insurgents affiliated to al-Qaida, requesting aid in southern Somalia, but said the inability of food agencies to work in the region since early 2010 has prevented the UN from reaching the very hungry – especially children – and has contributed to the current crisis. The Bakool and Lower Shabelle regions are understood to be controlled by al-Shabaab. The UN refugee agency, the UNHCR, said it was seeking further security guarantees from the rebel group that it can deliver greater amounts of assistance in the area to prevent more hungry people from becoming refugees.