The cause of the explosion is not yet known, District Superintendent of Police Vishal Gunni said.
SPS Nellore district Collector Revu Mutyala Raju and SP Gunni rushed to the spot to over the rescue operation.
Deputy Chief Minister (Home) N China Rajappa spoke to the district SP over phone and directed him to ensure better medicare to the injured.
He directed the SP to conduct an inquiry into the incident and submit a report immediately.
The Deputy CM also asked the district administration to crackdown on illegal cracker manufacturing units, if any.
Meanwhile, sources said the toll might go up as many suffered serious burns in the incident.