A food aid ship seized by Somali pirates three months ago has left the port where it was expected to unload, aid workers say.
Some 28,000 people affected by the tsunami need food aid
The MV Semlow was carrying World Food Programme aid for Somali victims of the Indian Ocean tsunami, when it was seized off the Somali coast in June.
After extensive negotiations, the pirates docked the ship on Monday.
But they are believed to have made new demands as the authorities prepared to unload the cargo of 850 tons of rice.
The pirates had initially demanded $500,000 in ransom, but the WFP says no money was paid.
After docking at the port of Elmaan near Mogadishu, the ship has now returned to sea with the cargo and crew still onboard, WFP officials say.
The crew comprises eight Kenyans, a Tanzanian and their Sri Lankan captain.
The ship was captured off Haradere, north of Mogadishu, after sailing from Mombasa in Kenya.
WFP provides an average of 3,000 tons of aid a month to 275,000 people in Somalia.
But its work is hampered by concerns over security. The country has had no functioning national government since 1991.
The International Maritime Board has warned of an alarming increase in piracy in Somali waters and has urged ships to avoid the area.
Last month, three smaller fishing vessels were hijacked by gunman off the southern port town of Kismayo and some 40 crew members are being held hostage.