The deterioration is due to the cumulative effects of conflict, insecurity and civilian displacement within the Shabelle region, "which [have] led to stress on host communities with IDP [internally displaced persons] influx and sharp inflationary price increases over the last three months", the UN Food and Agriculture Organization's Food Security Analysis Unit (FSAU), said in a statement.
FSAU said the impact of recent shocks was now manifesting itself through increasing rates of acute malnutrition which, as of May 2007, were above the emergency threshold of 15 percent.
"Even more worrying are the extremely high rates of severe acute malnutrition of 4.9 percent and mortality rates also above the alert threshold," FSAU said.
Aid workers estimate that about 400,000 people have fled the capital, Mogadishu, since February, to seek shelter in other regions of the country, particularly in Lower and Middle Shabelle. Many have, however, returned to the city.
The agency said the 'Gu' (April-June) rains, the most important of the year, have been below normal and coverage for most of the country has generally been well below normal in most agricultural areas in the south, both for rain-fed and irrigated cereal crops.
Displaced populations, including those who remained outside Mogadishu and those who returned, also still require urgent aid, while many of the returnees found their homes destroyed. Food and medical care were in short supply and business activities were limited in some neighbourhoods, as were options for people to support themselves, the agency said
Somalia, which has been without an effective government for one-and-a-half decades, has witnessed clashes between Ethiopian-backed government troops and insurgents since February, hampering efforts to deliver aid to those affected.
Meanwhile, the UN will shift its focus from providing assistance to the thousands of displaced to providing basic services, the UN Office for the Coordination of Humanitarian Affairs (OCHA) has said.
"While the first phase of the IDP response prioritised assistance to the most vulnerable, given that returns to Mogadishu have begun, the focus will now shift to provision of basic services to IDPs and the community as a whole," OCHA Somalia said on 15 June.
At least 112,000 people have returned to their homes in the capital, Mogadishu, since 1 May (99,000 in May alone), though the numbers could be higher, the agency said.
However, the returnees face uncertainty over shelter - especially families that lived in government buildings for the past 16 years. Moreover, many buildings that housed IDPs were destroyed in the recent violence.
Transport difficulties have also hindered the return of more displaced families, with reports indicating that IDPs trying to return have had to wait up to three days for transport, according to OCHA.