Gunmen have ambushed a United Nations food convoy in Somalia, sparking a gun battle in which two escorts were killed and nine people injured.
The gunmen struck near Baidoa, seat of the interim Somali parliament, police and relief workers said.
The 72-lorry convoy managed to return to Baidoa with all its cargo of maize, beans, cooking oil and porridge intact.
An MP from the interim parliament tried to negotiate with the gunmen but was himself injured.
A BBC correspondent says that many militiamen who moved out of Baidoa several weeks ago to allow politicians to work there have now returned to the town, adding to the climate of insecurity.
More than two million people are at risk of starvation and in need of urgent food aid in Somalia due to poor rainfalls.
Monday's convoy had been heading for drought-stricken areas outside Baidoa.
The gunmen had reportedly demanded a share of the aid
Those killed were militiamen hired to escort the World Food Programme (WFP) convoy and four of the wounded were also guards.
"The shoot-out was short but intense and I never thought we would survive," one driver told AFP news agency on condition of anonymity.
The MP, Ibrahim Abdullahi Osman, said the attackers had demanded a share of the aid before the shooting started.
"We understand that the gunmen have no jobs, nor have they been encamped for rehabilitation, therefore they are hungry, but still we can't accept them when they try to use force to take the food aid intended for their parents and the poor," the Associated Press news agency quoted him as saying.
WFP spokesman Peter Smerdon said the organisation regretted the deaths.
"We've noted substantial efforts by authorities in Baidoa to protect humanitarian workers and ensure that aid reaches those who need it," he said.