HANGZHOU - A blast ripped through a factory in East China's Zhejiang province Sunday, killing three people and injuring three others, local authorities said.

The blast occurred at 9:20 am at a factory making insulating materials in Changshan county, the county government said in a statement.

The blast also triggered a fire and it was put out about two hours later, the statement said.

The three injured were described in stable condition, it said.

The cause of the blast is under investigation, it added.