People were reportedly evacuated from an Islamic faith school in Sheffield last night following the discovery of gas canisters nearby.
Witnesses claimed gas canisters were "placed and left open" at the Cube Foundation in Darnall yesterday evening - which provides an after school Madrassa for children.
A witness, who did not want to be named, said: "The building is on two floors and the second floor is where the children were studying. The canisters were placed on the ground floor. One of the workers noticed them and contacted the police.
"I've driven past and there were police cars and all the children had been evacuated."
Emergency services confirmed they had been called out to deal with an incident at about 6.15pm.
A South Yorkshire Police spokesperson said officers "in partnership with South Yorkshire Fire and Rescue, assisted members of the Balfour Road mosque with the discovery of discarded medical oxygen cylinders.
"There was no risk to any members of the public and the items have been taken for suitable disposal."
The spokesperson added: "It is thought that this was a case of littering, rather than anything malicious."
A South Yorkshire Fire and Rescue spokesperson said: "Firefighters from Rotherham Station were called out to the scene. Two discarded propane medical cylinders had been left in the street and nobody seems to know why.
"A cordon was put in place around them while the cylinders were removed as a precaution. We left the scene at about 7.30pm."
Nobody from the foundation has been available for comment yet.
The Cube Foundation was founded in 2002 "to create a place, a hub where all members of the community could come together for the common good of all without the politics of culture, sectarianism, groupism or other prejudices."
A statement on the organisation's website adds: "Our areas of concern include the promotion of the Islamic faith, the promotion of education, empowering the youth, promoting care for the environment and helping the vulnerable and needy through welfare and relief work in the United Kingdom and abroad."