One of the bombs appeared fairly small but the other was huge, officials said. At least one bomber was on a motorcycle.
The attackers exploded their bombs near the office of Rasool Khan, a deputy Mohmand administrator who escaped unscathed.
According to Amjad Ali Khan, Mohmand chief administrator, tribal elders, including those involved in setting up militias to fight the Taliban, were in the building, but none was hurt.
Mohmand is one of several areas in Pakistan"s lawless tribal belt where Taliban and al-Qaida members are believed to be hiding.
Pakistani Taliban spokesmen could not be immediately reached after the attack. There were scattered reports the militant group"s branch in Mohmand had claimed responsibility and said it was targeting the elders.
Several video footage showed dozens of men searching through piles of yellow brick and mud rubble for survivors. Women and children were among the victims.