The British public has donated £42 million in just over three weeks to help drought victims in East Africa, it was announced today.
More than £1 million of that amount was raised by donors using SMS texting to send money.
The Disasters Emergency Committee (DEC), an umbrella organisation for 14 of the UK's leading aid agencies, said the show of generosity was "a wonderful example of public concern" for those affected by the region's worst drought for 60 years but added the crisis is getting worse.
The DEC East Africa Appeal said more than 10 million people in Ethiopia, Kenya, Somalia and the newly formed Republic of South Sudan are in need of food, water and emergency healthcare.
Brendan Gormley, chief executive of the charity group, said: "To raise £42 million in just over three weeks is a wonderful demonstration of public concern for those in need.
"We can't lose sight of the fact, however, that this is an escalating crisis. It is now for the UN to act and for governments worldwide to dig deep to alleviate the suffering.
"The UN assessment of what is needed in Ethiopia, Kenya and Somalia, for example, stands at nearly 2.5 billion US dollars (£1.5 billion). Less than half of that has so far been received from donor nations.
"Similarly, in South Sudan, the UN has called for 620 million dollars (£381 million), much of which is to tackle food shortages caused in the fragile new state by drought and displacement. The amount that has actually been raised is 324 million dollars (£199 million)."
The drought in parts of East Africa has devastated cattle and crops, with problems expected to be compounded by a poor coming harvest.
The situation is so serious that famine has been declared in two regions of Somalia, with other areas expected to follow, the DEC said.
Speaking of the surge in donations through text message, Polly Gilchrist, fundraising manager at the DEC, said: "We are delighted to have shown that there is a new audience out there that want a quick and easy way to make donations in a way that is relevant to them. Asking people to use their mobiles has paid dividends.
"This lays to rest scepticism about whether texting works as a method of giving funds.
"As of today we have raised £1,063,000 by this method, which with Gift Aid comes to more than £1,250,000.
"This is over 500% more than we have raised from texting in the past. It is also encouraging that more than 60% of SMS donors have responded to the request for Gift Aid details, which means nearly 25% can be added to the value of their donations."
The donations announcement comes as tens of thousands of famine-stricken Somali refugees were left cold and drenched after torrential rains pounded their makeshift structures in the capital, as the UN raised concerns that renewed conflict in the country may jeopardise relief work.
Rains are needed to plant crops and alleviate the drought that has led to famine in Somalia, but added to the misery of many refugees who live in structures made of sticks, flattened milk cans and pieces of cloth.
Refugees in several camps in Mogadishu have said that more aid is needed.
Refugee Abdi Muse Abshir said: "We are living in plight, we left our homes, lost our animals and farms so we ask everyone to help us to survive."
Lul Hussein, a mother of five, said her family had a sleepless night after their makeshift home crumbled.
"We are starved and we don't have enough help," she said. "Who's helping us? No one. So we are already between death and bad life."
Aid agencies have limited reach in Somalia where Islamist militants are waging an insurgency against the country's weak UN-backed government.
The UN fears tens of thousands already have died in Somalia in areas held by the Islamist rebels because food aid could not reach them.
On Sunday, Pope Benedict XVI urged the world not to forget the victims of famine in the Horn of Africa during his weekly blessing to pilgrims.
"It is forbidden to be indifferent in the face of the tragedy of the starving," the Pope said from his summer residence in Castel Gandolfo, south of Rome, Italy.
The Pope invited the faithful "to think of the many brothers and sisters who in these days, in the Horn of Africa, are suffering the dramatic consequences of famine, aggravated by war and the absence of solid institutions".