A small explosion rocked the National Medical College and Hospital in the city injuring two persons, police sources said today.

Two sweepers of the National Medical College Hospital were injured when a plastic container containing some carbide material exploded with a bang when they tried to shake it, the sources said.

No patient was, however, injured, police said.

The bomb squad personnel have arrived at the hospital.

The Medical College Principal, Shiddhartha Chakraborty, said normal hospital services were not affected.