Badrudin Ahmed Kamran, Mayor of the northeastern shrine city of Sylhet, was at a ceremony to open a badminton tournament when unidentified assailants hurled a powerful grenade at him on Friday. However, the grenade did not explode and the mayor escaped unhurt.

No one has claimed responsibility for the attack and no arrests have been made so far, police said.

Kamran, who belongs to the main opposition Awami League led by former Prime Minister Sheikh Hasina, has been the target of attacks before also. The party has called a strike on Sunday in the city to protest against the attack.

Police said the bombs recovered were found in southwestern Khulna and northern Sirajganj districts among other places.

More than 70 suspected militants have been arrested since Thursday and security personnel raided suspected militant hideouts in capital Dhaka as well as elsewhere in the country.

However, the banned Jamaatul Mujaheedin Bangladesh militant group, believed to be behind the human bombings this week which claimed 12 lives and left over 100 injured, continued to send threats to individuals and institutions calling for establishment of Islamic rule in Bangladesh.

Meanwhile, the mainstream opposition has rejected government calls to find ways to tackle militancy through talks, saying instead that Prime Minister Khaleda Zia should resign.

Local Government Minister Abdul Mannan Bhuiyan said he still hoped the opposition would pay heed to their call and that he would send a formal invitation for such a dialogue.