Bangladesh has launched a nationwide manhunt for 400 members of a banned Islamic militant outfit and its allies, suspected to be responsible for Wednesday's serial blasts across the country.

Chief of Jama'atul Mujahideen Bangladesh Moulana Abdur Rahman and Sddiqur Rahman alias 'Bangla Bhai', said to be the mastermind behind the bombings, top the list of the 400 wanted men prepared on Saturday, police officials said in Dhaka.

Image: Bangladesh Serial Blasts
400 crude bombs rock Bangladesh

"As it is now quite certain that this organisation carried out the attack, we are listing all its leaders and activists and trying to trace them," an investigator said, adding, "Law enforcers are keeping a strong watch on Abdur Rahman's den and madrassa in Jamalpur."

Although some intelligence officers believe Abdur Rehman and Bangla Bhai are now hiding abroad, we are continuing to look for them in the country, he said.

The list has been distributed among the police, Rapid Action Battalion and intelligence agencies in all districts, sources said.

Prime Minister Khaleda Zia, who returned home on Saturday cutting short a visit to China, was unhappy with the intelligence outfits for failing to prevent the bombings and was mulling major revamp of intelligence and security agencies.

Bangla PM terms serial blasts cowardly

Zia had detailed briefings with officials and changes were likely in the intelligence and other security agencies, the Daily Star newspaper said. Arrests in connection with the Wednesday's bombings continued across the country. So far 123 people have been taken into custody, the home ministry said.

The arrested were being brought at the joint interrogation centre in the capital. The home ministry said 434 bombs had exploded on August 17 and 51 unexploded ones were recovered. In Khula, intelligence agencies were keeping watch on 11 mosques of the Ahle Hadith sect, while most of the mosques had been cordoned off.

Meanwhile, the main opposition Awami League of former prime minister Sheikh Hasina Wajed mourned the victims of last year's August 21 grenade attack on a party rally in Dhaka on Sunday.

The attack killed 23 people and left scores injured, including Sheikh Hasina whose is still undergoing treatment for ear injury.