Afghan President Hamid Karzai said those responsible for a suicide bomb attack outside a mosque in the north of the county were "enemies of Islam and humanity."
Forty one people died and more than 50 were wounded in the attack on October 26
in Maymana, capital of northern Faryab Province.
Many of the casualties were senior regional officials, celebrating a major Muslim holiday.
No one claimed responsibility.
The NATO-led coalition's commander, U.S. General John Allen, also condemned the attack.
The attack was the latest in a series of deadly strikes in recent weeks against Afghan army, police, and government officials.
Earlier, Karzai repeated his call for the Taliban to join the government in an address to mark Eid al-Adha.
Elsewhere, the Taliban claimed responsibility for the deaths of two U.S. service members in southern Oruzgan Province the day before.
Based on reporting by AFP and AP