|An unidentified Afghan man walks as belongings of the victims are seen after a bomb blast at a mosque in Kandahar, Afghanistan|
President Karzai said the attack, which left at least 20 people dead and at least 52 more wounded, was an act by what he called enemies of Islam.
Mr. Annan expressed shock and outrage.
The mosque was crowded with mourners attending a funeral for a prominent pro-government cleric who was killed by suspected Taleban gunmen Sunday.
The police chief of Kabul was among the dead.
Officials say documents found on the body of the bomber show he was an Arab linked to the al-Qaida terrorist network.
Separately, a roadside bomb in Afghanistan's Helmand province killed at least two Afghan deminers and wounded another five.
Some information for this story provided by Reuters and AP.