Kolkata: A 14-year-old boy was critically injured when the object with which he was playing inside an abandoned hostel of a college here exploded today, police said.

Rintu Shaw was taken to the Calcutta Medical College Hospital when the round-shaped object he was playing with exploded inside the abandoned hostel of City College on Amherst Street at around 9.40 am, a senior officer of Kolkata Police said.

"The reason why the boy had entered the abandoned premises was still yet not clear. He had picked up a bag lying there which had a round object inside. The object, was probably an explosive, went off when he tried to play with it," the investigating officer said.

Police personnel from the local Amherst Street police station besides the bomb disposal squad and sniffer dogs were rushed to the place, he added.

The building, abandoned for several years, has become a den of all form of mischievous activities for miscreants, locals complained.

"We are looking into the matter. Our forensic experts are collecting evidences from the spot," the officer added. (PTI)