There were fewer attacks by Somali pirates in the first quarter of this year than during the same time last year, but their reach is extending far beyond the Gulf of Aden.
Militant Islamists have the moderate government surrounded in Mogadishu. If they took over, it would be a devastating blow to US counter-terrorism and anti-piracy efforts in East Africa.
Islamist militias' clashes with Somalia's government has forced more than 25,000 to flee.
The attack undermines a UN-mediated cease-fire signed last week between the government and opposition groups as the country's humanitarian crisis worsens.