THE HORN of Africa is in the grip of a devastating food crisis that has left up to 15 million people across the region in need of emergency food aid. A deadly combination of deepening drought and soaring food prices has led to huge rises in malnourished children in Ethiopia, Somalia, Djibouti, and parts of Uganda and Kenya.

But nowhere is the situation as severe as in war-torn Somalia, a country without a functioning central government since 1991 which aid workers warn is on the brink of a "hidden famine". An ongoing conflict, pitting Ethiopian and Somali government forces on one side against a variety of Islamist militias on the other, is having a catastrophic effect on relief operations.

As the humanitarian situation spirals dramatically out of control, aid workers face a new problem. The very people trying to help Somalia's hungry millions are now being targeted themselves. Twenty aid workers have been assassinated so far this year, the majority in the past two months, in what humanitarians fear is an "orchestrated campaign" of terror.

The UN previously estimated that as many as 3.5 million people from a population of about eight million would need emergency assistance by the end of the year, but that figure is now expected to rise. The rains failed in many parts of southern and central Somalia; in some areas it was the fourth consecutive season they had not come.

Water is so scarce that entire villages have been deserted as families move to get closer to a working borehole. But boreholes are in short supply and many are in bad shape. Water costs have rocketed - in some areas they have increased by 1000% in the last three months.

Getting food into Somalia is becoming impossible. Around 90% of the UN World Food Programme's (WFP) deliveries are supposed to come by ship, but rampant piracy off the Somali coast has meant most shipping firms are too scared to deliver food. European navies have been escorting WFP shipments since November, but since the last Dutch escort at the end of last month no other country has offered to help.

What food is inside the country is either too expensive or cannot be safely delivered to those most in need. Roadblocks set up by militia groups regularly attack aid convoys and five drivers working for the WFP have been killed this year.

The WFP's Peter Smerdon warned that if enough food wasn't delivered over the coming months "we could see scenes similar to the 1992/3 famine in which hundreds of thousands of people perished". With aid workers and journalists unable to access most parts of the country, Smerdon warned Somalia could suffer a "hidden famine".

Another aid worker, who wished to remain anonymous, added: "People will die and we won't see it, and until we see people dying there won't be an international outcry against this."

Hopes for peace were raised, briefly, last month when representatives from the fragile Somali government and the opposition Alliance for the Reliberation of Somalia (ARS) met in Djibouti. But no sooner had the two sides agreed on a tentative framework for further talks than the violence in Mogadishu and elsewhere surged.

Analysts say there are hardline spoilers on both sides who do not wish there to be a working peace. While the prime minister, Nur Adde, a former president of the Somali Red Crescent, has been insistent that a peace deal is necessary his president, former warlord Abdullahi Yusuf, who still controls the security apparatus, is less keen.

On the opposition side, the relatively moderate Sheikh Sharif Ahmed, who agreed the deal in Djibouti, was last week ousted from his position as ARS leader by Shiekh Hassan Dahir Aweys, a hardliner who has been placed on the United States' list of suspected terrorists.

It is not the first time the two men have fought for power. Both were leaders of the Union of Islamic Courts, which briefly held power in Mogadishu and large swathes of southern and central Somalia in 2006.

Ahmed backed talks with the government, Aweys backed jihad against Ethiopia. Aweys came out on top, but his strategy failed. Ethiopian troops used Aweys's threats as an excuse to invade over Chirstmas 2006. The Courts' fighters were routed within days.

By the end of January 2007 though, militias linked to the Courts had returned, launching an Iraq-style insurgency against Ethiopian and Somali government troops. Most fighters belonged to a group known as al-Shabaab, "the youth", which the US has claimed has links to al-Qaeda. In the past 18 months their leaders have been targeted by a series of US missile strikes.

Despite claiming to be fighting for the Somali people, al-Shabaab has targeted humanitarian relief operations in the areas of southern Somalia it controls. It has warned that any Western aid worker found in its areas will be killed, as will any Somali helping them.

As a result, many were quick to blame al-Shabaab as the assassination of aid workers increased. But in recent weeks, diplomats and analysts have also begun to suspect the involvement of groups and individuals linked to the government, which is backed by the UN and funded by the EU and the UK.

"All sides are involved, including hardliners in the government," one Nairobi-based analyst said.

The growing levels of violence have led to calls for a UN peacekeeping force to be sent to Somalia. At present, a small and limited African Union force of fewer than 2000 is able to do little more than protect government institutions such as the airport and the presidential villa.

The UN's special envoy to Somalia, Ahmedou Ould-Abdallah, last week urged the UN to step in, but analysts fear a repeat of the UN's troubles in Darfur if a peace agreement which includes all the main players is not in place first.