A bomb exploded on Monday on a bus carrying UN employees in northern Somalia, killing at least 10 people and wounding many others, police and UN officials said. The al-Qaida-linked al-Shabab group claimed responsibility for the attack.

Both foreigners and Somalis were casualties of the attack in Garowe, the capital of the semiautonomous Puntland region, said Ali Salad, a senior police officer in Puntland.

"It's a dark day, but terrorists must know that the blood they shed will not go in vain. We shall deal with them with an iron hand," Salad said.