"We raided an abandoned truck in the port area and seized 49 sealed packets containing over 25,000 bullets of AK-47 rifles," Kolkata police chief Sujoy Chakraborty said.

He added this was the biggest weapons haul in recent history.

The truck carrying bamboo sticks reached the city's port area from India's northeast about a month ago and was parked in the area, he said.

"The vehicle was likely to leave for Jammu and Kashmir within a day or two," he said.

Tipped off by intelligence officials, police raided the vehicle at about 4 pm (local time) and found the packets of bullets concealed in an upper berth inside the driver's cabin.

"Kolkata has been a transit route of terrorists," Chakraborty said.