Five persons were killed and at least three critically injured on Saturday in an explosion at a waste dump in the northern Indian town of Meerut in Uttar Pradesh state, police said, according to DPA. A group of waste collectors were sorting out rubbish in the Bengali Basti area when a mortar shell discarded by the army exploded, senior police official Raghuveer Lal said. The victims were boys aged between 10 and 19, the police said. The three injured had been admitted to hospital. The police found some further live mortar shells at the site and defused them. The waste dump is located near a slum housing Bangladeshi immigrants, PTI news agency reported. Meerut, located about 65 kilometres north-east of the Indian capital, is a communally sensitive town with a large Muslim population. There have been a series of terrorist blasts in major Indian towns since May and the police were quick to confirm that the blast in Meerut was an accident. "The blast took place when the victims were trying to extract copper from a live mortar shell," Meerut's inspector general of police Guru Darshan Singh was quoted as saying by IANS news agency. The slum is located near an army firing range and the slum dwellers often tresspass in search of scrap according to army officials, Singh said. Scrap is routinely collected by a contractor appointed by the army after a firing exercise but some shells and mortars often get buried in the soil and these are collected by young ragpickers who then try to extract metal from them, Singh said. "We will be taking precautionary measures to avoid such incidents in future," Singh said.