The bomb is likely to be defused with the help of officials from the Ordnance Factory. (Representational)

A 1000-pound aerial bomb dating back to the World War-II era has been unearthed at a dock in Kolkata during routine dredging operations.

The area was cordoned off following the discovery of the bomb Friday and the police, Navy and the Army duly informed, Kolkata Port Trust Chairman Vinit Kumar said.

"The 4.5-metre-long aerial bomb was located around 2 pm yesterday during dredging operations at Netaji Subhas Dock berth II. Initially, we thought it was a torpedo, but the Navy has confirmed that it is a bomb," he told PTI.

The explosive is likely to be defused with the help of officials from the Ordnance Factory, he added.

Commodore Suprobho K De, naval officer-in-charge, West Bengal, said the bomb does not pose any risk as it has several

security locks affixed to it.

"It is a 450-kg aerial bomb fitted with brackets to attach with fighter planes. There seems to be no threat from the bomb as it has locks affixed to it. Also, aerial bombs have to be dropped from a certain height to make an impact," he explained.

Commodore De said there is not much that the Navy can do about the device.

"I hope the KoPT will seek help from the Ordinance Factory, which has expertise in making ammunition. If needed, we may contact Vizag naval base for assistance," Commodore De said.

Netaji Subhas Dock, on the east bank of Hooghly river, was extensively used by the US Navy during World War II for its operations.