Bangladesh security forces have arrested 87 people in connection with a wave of simultaneous bombings linked to a banned Muslim extremist group.
Two people were killed and more than 100 injured when around 350 small homemade bombs exploded within the space of an hour in almost every town or district across the country.
"We launched a nationwide crackdown and so far we have arrested 87 people," said Bangladeshi Inspector General of Police Abdul Kaiyum, speaking to AFP.
"Our forces are everywhere. We are on the highest alert."
Leaflets were found at all of the bomb sites calling for the installation of Islamic law and signed by the outlawed Jamayetul Mujahideen group, banned in February for alleged links to a series of bombings of religious shrines and other targets.
Some of the leaflets also warned Britain and the US to leave Muslim countries, according to Special Broadcasting Service.
Many of the improvised bombs were placed in front of government offices, courts, hotels and bus and railway stations across the third-largest Muslim-majority nation in the world.
A police official said one detained suspect has admitted to being the local leader of Jamayetul Mujahideen.
"We are still questioning both men to get an idea about this organisation," said the official in Satkhira district, where two people are being held over five attacks.
Security has been tightened at all key installations in the Bangladeshi capital Dhaka.
The shooter freely entered the building of the university and opened fire at those who were present on the ground floor