"Through the yesterday's (Monday) blast, the terrorists are giving a message that they have gained ground in Kolkata and the NIA should go slow on the Burdwan probe," Bharatiya Janata Party national secretary Siddharth Nath Singh told media persons here.
Accusing the ruling Trinamool Congress of having links with Bangladeshi terror outfits, Singh also accused the state administration of hushing up matters related to explosions.
"Similar to the Burdwan blast, there has been a blast in Kolkata in 2013 and another explosion in Malda where a Trinamool leader was involved. What is the status of the investigation in these? The Trinamool administration has made it a habit of putting a lid on all kinds of bomb blast investigations," he said.
The BJP leader who has repeatedly accused the Mamata Banerjee government of trying to cover the Burdwan blast probe, demanded the Trinamool to come clean on allegations of having "links with Bangladeshi terror outfits".
Meanwhile, police have said the explosion outside the NIA office might have been caused by firecrackers.
"Prima facie, there is no evidence of bomb blast as we have not found smell of explosives or remnants. We have found one or two eye witnesses and it is likely that crackers could have been used to play mischief," said Bidhannagar Police Commissioner Rajeev Kumar said.
He however said samples collected from the spot have been sent for tests and a detailed investigation is being carried out into the incident.
The explosion occurred near a bus stand outside a Central Reserve Police Force camp that also houses the temporary office of the NIA in Salt Lake area.