Government buildings and shops were destroyed by the blast, leaving victims buried under the rubble.
Local administration chief Rasool Khan said the death toll had risen after he and other officials had earlier put the number of dead at 65.
"Some bodies were recovered from the spot and some died in hospitals overnight," he told AFP, adding the toll could rise further as rescuers work to recover victims feared trapped.
Another local official, Mairaj Mohammad, confirmed the higher toll and said there were 98 people receiving treatment in different hospitals.
The attack was the deadliest in Pakistan since a car bomb destroyed a market crowded with women and children in the north-western city of Peshawar in October 2009, killing 125 people.
Pakistani Taliban claimed responsibility for Friday's blasts, saying the target was a gathering of pro-government tribal elders.