The explosions occurred yesterday near a Shia mosque in a busy market of Parachinar in Kurram tribal agency almost two hours before 'iftar', the sunset prayer when Muslims break their fasts during the holy month of Ramadan.
According to a hospital official, another 12 people have died taking the toll to 52, which also includes seven children.
Around 136 people are being treated for various injuries, he said, adding that at least 24 of them are still in a critical condition.
Most of the victims belonged to the minority Shia community who were buying eatables as part of daily preparations before breaking the fast.
Nobody immediately claimed responsibility for the attacks but the Taliban are active in the region and target civilians and security forces.
The Shia community constitutes 20 per cent of population in Pakistan.