An explosion killed at least 15 children and wounded another 20 in the east Afghan province of Ghazni, officials said.
The reason for the explosion in the Gilan district is unclear with officials saying a bomb went off in the back of a rickshaw.
But local residents suggest a piece of unexploded ordnance blew up when children tried to sell it to a vendor.
Taliban militants also say the blast was accidental.
The explosion happened around 14:00 close to a house in a village where a Koran recital ceremony was underway.
A bomb went off after a man driving a motorised rickshaw entered the village and was surrounded by children, Wahidullah Jumazada, a spokesman for the Ghazni provincial governor, was quoted as saying by AP.
Police spokesman Ahmad Khan accused the Taliban of carrying out an attack.
Giving a lower death toll of 12, Taliban spokesman Zabihullah Mujahid said children had brought unexploded ordnance to the vendor and it had exploded.
Violence involving the Taliban has also continued despite peace talks between the group and Afghan officials in Doha, Qatar.
The negotiations, which have seen some progress on preliminary issues, have now been paused until January.
The two sides are yet to begin discussing a ceasefire or power-sharing arrangement.
Last month the US announced plans to withdraw 2,000 troops from the country by mid-January.