Kolkata, Jun 30 (IANS): One person was injured Saturday in a blast at a state-run hospital here, said an official.

The blast occurred in the National Medical College and Hospital (NMCH) when sweepers were cleaning the outdoor area, said West Bengal Minister of state for Health Chandrima Bhattacharya.

"One sweeper was injured. He has been admitted to the eye ward of the hospital. But no patients were injured," said Bhattacharya.

"It seems some miscreants kept an explosive substance outdoor, which went off. The police and bomb disposal squad personnel are at the spot. They have conducted a thorough search and given us permission to open it," she said.

The minister said the hospital authorities have been asked to hold an inquiry and give a report by Sunday.

"If it is found that somebody attached with the hospital is involved, we will take the strongest possible action," she said.

NMCH principal Siddhartha Chakraborty said when sweepers were cleaning the outdoor area they found one green packet lying on the floor. "As they threw it out, it hit the wall and exploded."

Sweeper Amit Das suffered splinter injuries in his hand, leg, eye and stomach.