The most high-profile militant to be arrested has been described as the operations head of the Jamaat-ul-Mujahideen - a group accused of carrying out the first suicide bombings in the country.
Ataur Rahman Sunny was detained in a raid early Wednesday along with several other suspected Islamic militants in the capital Dhaka. Police say he is the younger brother of the fugitive head of the Jamaat-ul-Mujahideen.
Bangladeshi officials on Thursday called his arrest a major breakthrough.
The arrests came in the wake of a massive security operation following a string of deadly bombings. The attacks, which targeted judges, lawyers, journalists and politicians, have killed more than 30 people since August.
Police say they have tightened security to prevent more attacks, particularly in Dhaka, as the country prepares to celebrate the 34th anniversary of its independence on Friday.
An independent political analyst in Dhaka, Ataus Samad, says authorities were particularly worried by last week's suicide attack, which killed several people in the small town of Netrokona.
"The suicide attacks really made it very worrisome for the government, and they went all out, particularly after the attack at Netrokana, where the bomb blast took place on a street, so the government thought they will not only attack selected targets, but also the public," Mr. Samad says.
Officials in Dhaka reiterated Thursday that the government is serious about ending Islamic militancy and said the arrested men will be put on trial. In the past, the government has been accused of dragging its feet on rooting out extremist groups because two hard-line Islamic parties are members of the ruling coalition.
Ajai Sahni, the head of the Institute of Conflict Management in New Delhi, says it is too early to say whether the government has the resolve to take stringent action against the militants.
"Whenever a great deal of pressure is generated on the government in Bangladesh to take action against the militant groups, we see a flurry of arrests, but we also discover that there is no permanent, long-term action taken against any of these groups or their members, there are no convictions, prosecutions fall by the wayside," Mr. Sahni says.
Bangladesh has a largely Muslim population but is governed by secular laws. Groups such as the Jamaat-ul-Mujahideen demand the imposition of strict Islamic rule.