Officials say a large quantity of explosives were involved
At least nine people, seven of them children, have been killed in an explosion at a house in Punjab province in Pakistan, hospital officials say.
Police said explosives appeared to have detonated in the home of a cleric who taught religious education to children.
Police say about 50 people were hurt in the blast near Khanewal south-west of Lahore. Many other houses collapsed.
It is not clear what caused the blast. Taliban influence has been spreading in Punjab, BBC correspondents say.
Punjab's main city, Lahore, has been the target of deadly attacks in recent months, including one on the Sri Lankan cricket team in March.
Pakistan's military is currently in the middle of operations in its north-west to clear the Swat valley and South Waziristan regions of Taliban fighters.
District co-ordination officer Kamran Khan said that the blast went off in a teacher's house, where Koranic lessons for children were regularly held.
Mr Khan said: "The blast was heard over a vast area and from the extent of damage it has caused it looks like a large quantity of explosives was involved.
"The people of the village say they saw a flame rise to the sky and then the ground shook like in an earthquake."
Police say there was an ammunition dump in the home located in the Mian Channu area of Khanewal district. But officials said they do not know what caused the explosives to go off.
Diggers uncovered a steel trunk from the debris of the house which contained pamphlets, CDs and audio tapes.
The tapes were said to be mostly of sermons by clerics linked to the banned Lashkar-e-Jhangvi (LJ) group, a Sunni extremist organisation close to the Taliban and heavily involved in sectarian killings in Pakistan.
The BBC's M Ilyas Khan in Islamabad says this would suggest the arms dump belonged to Lashkar-e-Jhangvi and that the place was being used by the militant group to indoctrinate children.
Dr Naim Sadiq, a hospital official, said the dead were seven children, one woman and a man.
Witnesses said no bodies had so far been recovered from the rubble of the house where the blast went off.
The dead and injured were mostly recovered from the debris of ruined houses nearby.
Television footage showed police collecting evidence from a crater about 40ft (12 metres) wide and nearly 8ft (2.5 metres) deep.
Small rockets and missiles propelled by shoulder-fired launchers were among the other material recovered, said police.
Civil defence officials are scanning the area with metal detectors, witnesses say.