At least seven people died and 59 others were injured in an explosion at a kindergarten in East China’s Jiangsu Province on Thursday, AP reported. Quoting government officials, the news agency said the blast took place just as the children were leaving the premises.

Purported footage of the blast had showed several people, including children, lying on the ground, Global Times reported.

Officials said the cause of the incident is being investigated. Local emergency services personnel are at the Fengxian county establishment.

Kindergartens have been a target of “revenge attacks” by rival groups in the country, AP reported.