Four boys aged just nine have been suspended from school after being found with cannabis, education officials said.
They were found with a small amount of the drug in the playground at Cherry Fold Community Primary School in Burnley, Lancs, on Friday.
Police were called to the school after the pupils were found with the class B drug, and all the boys have now been excluded from the school pending an investigation.
Officers spoke to the boys and their parents and issued each of the youngsters with a youth referral order.
The mother of one of the suspended boys, according to local reports, claimed some of the boys were dealing drugs with amounts being sold for 50p.
A tea bag-sized amount of cannabis plant, not resin, was found and Lancashire County Council said drugs were not being dealt at the school.
Lancashire Police have said there is no evidence pupils were dealing cannabis.
Deanne Marsh, acting headteacher at Cherry Fold Community Primary School, said: "I can confirm that four pupils are currently not at school while investigations are carried out into an incident at the school.
"It would not be appropriate for me to comment further as we take our pupils' confidentiality and safety very seriously and we are still looking into all the circumstances."
A police spokeswoman said: "We were called to the school following reports that four children had been found in possession of cannabis. Officers spoke to the children and their parents and issued youth referral orders."