Aid agencies warn that recent heavy fighting in Somalia, including Kenya's military assault in the south, is deepening the world's worst humanitarian crisis in the war-torn nation.
Fighting has choked aid deliveries and blocked civilians trying to escape across the border into Kenya, while heavy rains have raised the risk of water-borne diseases – potentially fatal for a weakened population.
The United Nations estimates that 3.7 million Somalis – around one-third of the population – are on the brink of starvation and tens of thousands have already died in a country that has lacked effective government for two decades.
Civilians who have already fled extreme drought are now "facing multiple displacements in the wake of the military activities," the UN Office for the Coordination of Humanitarian Affairs (OCHA) warned.
"The military build-up is causing anxiety among the civilian population," it said. "Movement of humanitarian personnel and supplies are also likely to be restricted, subsequently affecting the timely delivery of assistance to populations in need."
Kenya's unprecedented military incursion 11 days ago, launched after attacks on its territory and the abduction of several foreigners on its soil who were taken to Somalia, stunned the region.
Oxfam warned that the situation in Somalia is “increasingly alarming," adding that famine zones are "expected to spread over the next month, including to some of the regions that are now facing further conflict."
"Kenya has legitimate security concerns, and has already welcomed a huge number of refugees, but it must continue to ensure that people can seek safety and shelter," it said in a recent statement.
Kenyan troops have pushed some 100 kilometres (60 miles) into southern Somalia, areas controlled by the Shebab militants, but are restricting routes for civilians fleeing fighting, aid workers say.
"Continued insecurity and military activities at the Somali-Kenya border have restricted movement, causing a sharp decline of Somalis entering Kenya to 100 last week, down from 3,400 a week before," OCHA said.