The Sinn Féin leader has met with families impacted by the Creeslough explosion and is backing their call for answers about what happened.
Mary Lou McDonald is also calling for the Justice Minister to meet the families without delay.
She says there needs to be a public inquiry into the deaths of 10 people in the village in October 2022.
"Our hearts go out to these families. They have suffered just enormously unthinkable grief. They should not be left in limbo in this way. We believe that that is cruel and unnecessary. So we want to say very clearly to Jim O'Callaghan, please organise this meeting without delay and please allow for the public enquiry to commence alongside the criminal investigation."