A ship carrying United Nations' food aid to Somali victims of the Indian Ocean tsunami has been hijacked.
The WFP is feeding 28,000 people affected by the tsunami
The freighter, the MV Semlow, was sailing from the Kenyan port of Mombasa to Bossaso in north-eastern Somalia when it was attacked by armed pirates.
Waters off the Somali coast are among the most dangerous in the world, the International Maritime Boards says.
Some 28,000 people who lost their homes and livelihoods when the tsunami struck on 26 December are being fed by the UN.
Somalia is awash with some 60,000 militia men and has been without a functioning national government since 1991, which hampered relief efforts to tsunami victims.
Attempts to relocate a new tranisitional administration - set up in neighbouring Kenya last year - back home have so far failed.
The 10-member crew onboard when the MV Semlow was captured by gunmen on Monday morning between Haradhere and Hobyo, some 300km (190 miles) northeast of capital Mogadishu, are reported to be safe.
"The hijackers are asking for $500,000 but we've told them we're just a small boat with relief cargo to feed your Somali people," Inayet Kudrati, director of the Kenya-based Mokatu Shipping Agency which leased the ship to the UN, told Reuters news agency.
The UN World Food Programme (WFP) has appealed for the immediate release of the vessel carrying food aid donated by Japan and Germany.
"We're urging local leaders and elders to allow the boat to go on with its journey," WFP spokeswoman Rene McGuffin said.
Earlier this month, the International Maritime Board warned of a surge in piracy in the region and advised vessels to stay at least 85km away from the lawless coast if possible.
Damage from the tsunami was concentrated on the north-eastern coast of Somali, killing up to 200 people, smashing 2,400 fishing boats and displacing as many as 30,000.