An explosion blew off portions of the walls of an apartment in Titagarh near Kolkata on Monday morning, the police said.
Three persons, including a Trinamool Congress councillor, were arrested in connection with the blast on BT Road, they said.
The incident happened in the congested Ward 4 of Titagrah Municipality in North 24 Parganas district, triggering panic in the area, a police officer said.
Titagarh Municipality Councillor of the ward Arman Mandal and two others have been arrested, he said.
An initial probe revealed that the flat was taken on rent by Mandal, the officer said.
"There was nobody inside the flat when the explosion took place. We suspect there were explosives kept inside the apartment. Investigation is underway," he said.
A shanty beside the apartment was also damaged as concrete debris fell on it after the explosion, he added. -- PTI