"We have seen the hostages this morning and they are doing well but the militiamen are insisting on a ransom being paid for their release," Mohamed Ali Yunus, a local clan elder who is involved in the negotiations, told AFP.

"They did not ask for a specific amount of money but they said that they needed some money to release them," he added.

Members of the local aid community also said that the kidnappers were demanding a ransom for the doctors’ release.

"The militiamen are accusing the local authorities in the region of levying taxes from the aid agencies and receiving no share," one aid worker said on condition of anonymity.

"Their aim is to get some money to release the aid workers," he added.

Another elder in the region was hopeful the kidnapping could be resolved quickly. "We are hopeful that the gunmen will release the aid workers peacefully, soon after our negotiations come to an end today," Edin Malag said.

Kidnappings of foreign aid workers and journalists by ransom-seeking armed groups are frequent in conflict-wracked Somalia.

UN agencies attempting to deliver food aid to the 3.25 million Somalis it estimates need humanitarian support have been repeatedly targeted.

Four World Food Programme employees have been killed in the Horn of Africa country since August last year.

Four European aid workers employed by the French NGO Action Contre la Faim (Action Against Hunger) and their two Kenyan pilots have been held hostage since November.

The spate of kidnappings has complicated the delivery of aid to the most affected populations in Somalia, long plagued by civil wars and humanitarian emergencies.

Somalia has had no effective central authority since the 1991 ousting of former president Mohamed Siad Barre touched off a bloody cycle of clashes between rival factions.

AFP/Expatica