Two policemen and an unidentified woman were killed Thursday in a bombing at a Muslim religious ceremony in northern Bangladesh, police and media reports said.

At least 12 other people were injured when explosives were detonated near a large congregation offering prayers in Kishoreganj district, around 100 kilometres north-east of the capital Dhaka, police officer Meer Mosharraf Hossain told local media.

At least one of the bombs exploded at a prayer meeting where hundreds of thousands of people had gathered for the Muslim holiday of Eid-al-Fitr, marking the end of Ramadan.

The country's information minister said the target of the attack was a police convoy patrolling the religious gathering. The blast killed one police officer and one other person, Minister Hasanul Haq Inu said.

"Up to nine police constables have been injured in the attack," Inu told Indian broadcaster CNN-News 18.

The violence comes just days after the country suffered a deadly hostage crisis in which 28 were killed, including 20 hostages, two policemen and six of the attackers. It was the worst in a recent wave of extremist attacks in Bangladesh.

The government has blamed homegrown militant groups of waging the violence in order to create political chaos in the country and undermine the secular government.