U.N. agencies say pirates are raiding ships in the waters off the Horn of Africa, including ships carrying food and medicine for Somalis in desperate need of humanitarian assistance. The agencies are issuing a call for coordinated international action to stop the pirates. For VOA, Tendai Maphosa has this report from London.

The World Food Program's Josette Sheeran and the secretary general of the International Maritime Organization, Efthimios Mitropoulos, are urging the United Nations Security Council to address the issue of high-seas piracy.

In a joint statement, the two officials say that delivering commercial and humanitarian supplies to Somalia has been a challenge ever since the collapse of the Siad Barre government in 1991.

Delivering relief supplies by land in Somalia has long been difficult because of the frequent roadblocks set up by militia groups across the country. But its political instability has also left the waters off its 3,000-kilometer coastline vulnerable to the pirate attacks. The pirates highjack cargo vessels for ransom and sell the goods they seize to buy weapons.

Greg Barrow of the World Food Program in London says a recent increase in pirate attacks appears to have led to higher shipping costs and a dramatic reduction in the use of cargo vessels.

Barrow says the transitional government in Mogadishu lacks the resources to police the waters, and because the attacks happen in Somali waters, foreign naval forces cannot take action.

"One possibility would be to invite naval forces that are already in the region into Somali waters to police those waters on behalf of the transitional federal government," he said. "One just can't take the decision to do this, one needs the permission of the transitional federal government before any steps like that can take place."

One way to get around this problem, says Efthimios Mitropoulos of the International Maritime Organization, is for the United Nations to put pressure on the Somali government to allow intervention by countries that have a naval presence off Somalia.