At least four workers were injured in an accidental blast at an ammunition plant of the Bharat Dynamics Limited in Hyderabad on Saturday.
TV reports said the blast took place when the workers were cleaning explosive waste material, TV reports said.
The injured workers have been admitted for treatment to the Apollo Hospital DRDL in Kanchanbagh.
While officials confirmed that four people were injured, media reports put the figure at six.
Bharat Dynamics Limited is an enterprise under the ministry of defence, which manufactures guided weapon systems.
Earlier, TV channels had reported that the blast occurred at the Defence Research and Development Lab.
Further details are awaited.