The UN's World Food Programme (WFP) has begun to airlift emergency food supplies to famine-struck Somalia.
The first flight, with 10 tonnes of nutritional supplements for children, has landed in the capital Mogadishu, an African Union official told the BBC.
Millions in Somalia and across the Horn of Africa face dire food shortages in the worst regional drought for decades.
The Islamist al-Shabab militia, which controls much of Somalia, has banned the WFP from its areas.
The delivery was to have begun on Tuesday but was delayed from leaving Kenya by bureaucratic hurdles.
Challiss McDonough, a spokeswoman for the WFP, said the 10 tonnes of Plumpy'nut, a peanut-based paste high in protein and energy, would be enough to treat 3,500 malnourished children for one month.
Given the demand for food aid in Somalia, the delivery is just a drop in the ocean, says the BBC's East Africa correspondent Will Ross, in Nairobi, Kenya.
The Plumpy'nut was flown from France to Kenya on Monday.
More flights were planned for the coming weeks, Associated Press news agency quoted Ms McDonough as saying.
Fleeing to Mogadishu
The delivery is the first airlift of food aid since the UN declared a famine in two southern areas of Somalia last week.
Similar flights are also due to take aid into the Ethiopian town of Dolo Ado, from where it can be moved across the border into Jubaland, a sliver of land held by Somalia's pro-government forces just west of famine-hit Bakool.
The aid is being moved by plane because sending it by boat would take months, said Ms McDonough.
Tens of thousands of Somalis have fled areas controlled by al-Shabab to Mogadishu and neighbouring Kenya and Ethiopia in search of assistance. The weak interim Somali government, backed by an African Union (AU) force, controls only parts of Mogadishu.
A spokesman for the AU force, Lt Col Paddy Ankunda, told the BBC the Boeing 737 delivering the 10 tonnes of supplies had landed at Mogadishu's airport.
The AU has 9,200 peacekeepers in Mogadishu to guard the airport and government-held territory in the city.
Somalia is thought to be worst-hit by the crisis, but Ethiopia, Kenya and Djibouti have also been affected.
More than 10 million people in the region are thought to be at risk.
Somali Foreign Minister Mohamed Ibrahim has warned that more than 3.5 million people "may starve to death" in his country.
The Prime Minister, Abdiweli Mohamed Ali, has complained that the UN is being too slow with the delivery of food.
The challenge facing all aid agencies is immense but some analysts are questioning why this emergency was not prevented - as the severe drought and food shortage were predicted late last year, says our East Africa correspondent.
After criticisms that wealthy Arab states were not doing enough to help with the crisis, Saudi Arabia has pledged $50m (£30m) to the WFP to buy food for Somalis, the UN agency has said.
It follows an announcement from the European Union that it would donate $40m on top of the $61m it had already given the drought-hit region of East Africa this year.