Six people were killed in the blast near the airport in the capital Mogadishu, for which the terrorist group al-Shabaab took responsibility.
"A vehicle exploded close to a convoy of U.N. vehicles at about 12:30 there today," U.N. spokesman Daniel Maclsaac said. "The U.N. in Somalia strongly condemns the attack and expresses deep sorrow at the reported deaths and injuries of Somali bystanders."
It appeared early on that no one from the United Nations was among the causalities. Three Somali soldiers were reported killed and eight people were injured.
Voice of America said it was told by sources that U.N. refugee agency's representative in Somalia, Alessandra Morelli, was traveling in the convoy.
Al-Shabaab, which has close ties to al-Qaida, said the target of the attack were "Western officials," China's Xinhua news agency said.