US officials say that the famine in Somalia has killed more than 29,000 children in the last 90 days.
Separately, the UN has declared that three new regions in Somalia are famine zones, making a total of five regions affected by famine thus far in the Horn of Africa country. The UN had said last month two regions were suffering from famine.
The Food and Agriculture Organisation (FAO), the UN's food arm, has said that famine is likely to spread across all regions of Somalia's south in the next four to six weeks.
Famine, as defined by the UN, refers to situations when at least 20 per cent of households face food shortages so severe that they are unable to cope with it and more than two people out of 10 000 people die daily.
Additionally, famine conditions are likely to persist until December, FAO said. Across Somalia, 3.7 million people are in crisis out of a population of 7.5 million, the UN says.
Al Jazeera's Peter Greste said that it was not just about getting food to Somalia but rather about getting nutritious food to the people suffering from famine.
"There is a real nutrition problem. They can get basic maize meal in here but that's not enough. There has to be nutritious food and that's simply not arriving," said Greste.
In need of assistance
The UN says 3.2 million are in need of immediate, life-saving assistance.
About 450,000 people live in Somalia's famine zones, according to Grainne Moloney, chief technical adviser for the UN's Food Security and Nutrition Analysis Unit at FAO-Somalia.
Somalia is suffering its worst drought in 60 years. Getting aid to the country has been difficult because al-Shabab fighters control much of the country's most desperate areas.
Mapping the spread of the Somalia famine
"Despite increased attention in recent weeks, current humanitarian response remains inadequate, due in part to ongoing access restrictions and difficulties in scaling up emergency assistance programmes, as well as funding gaps," the UN's Food Security and Nutrition Analysis Unit said.
Speaking on Thursday, Jacob Kellenberger, the president of the International Committee of the Red Cross (ICRC), said: "Somalia is what you could call a typical ICRC context.
"It is an armed conflict, compounded by a very serious drought. It is an area where people are already weakened since long years."
The ICRC has called upon donor nations to double its Somalia budget so it could help feed the more than a million people hit by famine in al-Shabab-controlled areas.
"Given the very serious, extremely worrying situation in the area, we came to the conclusion we had to increase very substantially our budget, which means our activities," Kellenberger said.
Earlier on Wednesday, an African Union official said a donor conference to raise money for Somalia famine victims had been postponed for at least two weeks.
A conference had been scheduled for August 9 to bring together African leaders and international organisations to address the drought crisis.
However, Valerie Vencatachellum, a senior AU policy adviser, said the conference had not been scheduled with enough advance notice.
Vencatachellum said it would be delayed at least two weeks so heads of state could attend.
Wafula Wamunyinyi, the deputy special representative of the chairperson of the African Union Commission for Somalia's (AMISOM), told Greste: "The African Union has not taken long. It has ... taken measures to ensure there is delivery of aid to the people who are displaced."
He said: "We're trying as far as possible to ensure that the delivery [of aid] reaches the people; that Mogadishu is kept secure; it is made conducive for the delivery [of aid] by the international actors to reach the people."
Referring to al-Shabab's presence, Wamunyinyi said: "If [Mogadishu] is not made secure, even the delivery of humanitarian aid will not be possible."
The UN said the prevalence of acute malnutrition and rates of crude mortality surpassed the famine thresholds in areas of Middle Shabelle, the Afgoye corridor refugee settlement and internally displaced communities in Mogadishu.
The Horn of Africa is suffering a devastating drought that has been compounded by conflict in Somalia, bad governance and rising food prices.
Tens of thousands of people have already died, and tens of thousands more have fled Somalia in hoping to find food aid at refugee camps in Kenya and Ethiopia.