Four pirates who are part of the gang that have hijacked a United Nations-chartered cargo ship in Somali have been arrested, aid officials say.
The UN said the authorities in Puntland arrested the gunmen when they went to purchase supplies in Bargal port
The hijacked ship, MV Rozen, had just delivered food aid to north-eastern Somalia when pirates seized it.
Piracy was rampant in Somalia but stopped last year when the Union of Islamic Courts (UIC) were in power.
Since the overthrow of the UIC at the turn of the year, Somalia has been descending back into the violence and chaos seen in the previous 16 years, and this latest incident raises fears of a resumption of lawlessness on the seas as well.
"The arrest is welcome but the safe release of the crew and the vessel remains our chief concern. We very much hope the ordeal will end soon," Peter Goossens, the UN's World Food Programme Somali country director, said in a statement.
Somalia's coastline was notorious for piracy
Four pirates are still aboard the hijacked vessel and the fate of the 12 crew is still unknown. The crew is composed of six Kenyans and six Sri Lankans.
Mr Goossens said the ship which had anchored six miles off the coast of Puntland region had started sailing southwards.
Initial reports indicated that the administration in Puntland had started negotiations with the pirates, but the WFP says no demands for ransom has been made.
On Monday, the UN said a US warship was heading towards the Somali coast.
The Rozen had delivered 1,800 tonnes of food aid to the semi-autonomous Puntland region and was returning to its home port of Mombasa in Kenya when it was seized on Sunday.
The Rozen was attacked last year off a port south of Mogadishu, but dodged the pirates that time, the WFP said.
In October, Kenya jailed a group of Somali pirates after they were captured by the by the US Navy off the Somali coast.
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