Nearly half an hour after the announcement of polls schedule, unidentified persons exploded at least four crude bombs at Nightingale intersection, close to the BNP headquarters.

No one was injured.

Salahuddin Mia, officer-in-charge of Paltan Police Station, said unidentified persons on a motorcycle hurled three to four crude bombs and fled away.

No one was arrested, he said, adding, police are investigating the incident.

Chief Election Commissioner Kazi Habibul Awal announced the polls schedule around 7:00pm and said the 12th general election will be held on January 7.