Two explosions were heard in Salt Lake’s Duttabad early on Sunday, residents said.

The explosions were apparently heard around 2.30am in the neighbourhood, off EM Bypass, where one or two-room houses, many of them shanties, stand cheek by jowl.

Nirmal Dutta, a Trinamul leader and the civic coordinator of the ward, said they woke up to the sound of the explosions. “We rushed out of our homes and saw dense smoke rising from a playground and an adjoining street,” said Dutta.

He alerted Bidhannagar South police station over the phone and a patrol team was sent to the area. The policemen and some residents went around the locality but failed to track down anyone responsible for the explosions.

“We have started an investigation and are looking for traces of explosives,” said the officer.

Ward coordinator Dutta alleged that some BJP workers were behind the explosions.

BJP leader Sabyasachi Dutta, who was earlier in the Trinamul Congress and had been a mayor of the Bidhannagar Municipal Corporation, said no one from his party had hurled bombs in Duttabad.

“It is not even clear whether the explosions really happened or were figments of imagination of the Trinamul ward coordinator and his followers. There is no reason why anybody would hurl bombs in Duttabad at night,” said Dutta, who led a rally in the area on Sunday demanding peace.