Bangladeshi authorities say a suicide bomb attack in the northern town of Netrokona has killed at least seven people, including the bomber, and injured more than 50 others.

Police and witnesses say a man drove a bicycle into a crowd during the morning rush hour Thursday.  They say that among those wounded was an alleged second bomber whose explosives failed to detonate.

No one has claimed responsibility for the blast. But authorities blame the outlawed Islamic militant group, Jumatul Mujahedin Bangladesh, which wants to impose strict Islamic law in the Muslim-majority, but secular, country.

The attack occurred despite a nationwide security crackdown imposed since a series of deadly bombings began in August. So far, 25 people, including two judges, have been killed. Authorities say security forces have arrested hundreds of suspects and confiscated large amounts of explosives, timing devices and other bomb-making material.

Some information for this report provided by AP, AFP and Reuters.