A Pakistani police officer says the death toll from the suicide bombing near the country's border with India has risen to 60, Fox News reported.
Nadeem Khokhar says Sunday's attack also wounded more than 100 people, who are still in hospital.
The bomber set off his explosives near a Pakistani paramilitary checkpoint on the outskirts of the city of Lahore, when hundreds of people were returning from watching an army parade.
Pakistan and India hold daily parades and flag-flying ceremonies on their respective sides of the border, drawing thousands of spectators.
The Pakistani Taliban splinter group Jamatul Ahrar has claimed responsibility for the attack.