Four people have been killed and 14 others injured in the second deadly explosion in southern China in two days.
The new blast sent huge plumes of smoke pouring from a fire in a garage in an industrial park in the commercial hub of Guangzhou.
Police said the cause was under investigation, although media reports said it appeared to have originated with explosive materials being stored at the site.
The blast follows one in a busy street outside a primary school in the southern resort city of Guilin on Monday in which two people were killed and 17 injured, including 10 children.
That was believed to have been caused by the detonation of explosive materials being transported on board a flatbed tricycle and city authorities ordered a safety crackdown in its wake.