A powerful blast ripped through a town near the Bangladeshi capital Thursday, wounding about 30 people, officials said, just two days after suspected Islamic suicide bombers killed seven people there.

The blast occurred outside a sprawling complex that houses the chief government administrator's office and a courthouse in the town of Gazipur, a police official said on condition of anonymity because he was not authorized to speak to the media.

Among the injured were four policemen, seven lawyers and three journalists, said a doctor at a local hospital, who also asked not to named in line with the official policy.

The attack comes two days after suicide bombers killed seven people in Gazipur and three more when a series of bombs went off outside a courthouse in the port city of Chittagong.

Officials blamed Tuesday's blasts on Jumatul Mujahideen Bangladesh, a banned militant group that seeks to establish harsh Islamic rule in Muslim-majority Bangladesh, which is governed by secular laws.

The group has targeted judges and lawyers, accusing them of following secular laws instead of Islamic Sharia rule.

Police detained nearly 50 suspects for questioning Tuesday and Wednesday in several districts, including two in Gazipur.