Sources in the intelligence agencies said that the far-flung chars (shoals) spread over Sirajganj, Jamalpur, Sherpur and Pabna districts have long been used as training camps by the JMB. Those are considered safe haven for the militants as it takes the law enforcers hours to reach there and thus allowing the JMB operatives enough time to flee a raid.
"We have kept our eyes on the northern region following the May 1 blasts at three railway stations and threats to blow up Hardinge Bridge," Director General of Rapid Action Battalion (Rab) Hasan Mahmood Khandkar told The Daily Star Monday.
He said the Rab is working to bust the militant remnants seeking to reform the fresh recruits into organised units. The elite force will soon go on an operation against them.
Recently, a JMB leader, under interrogation by Rangpur police, has admitted that Joyprotap Madrasa at a char on the Teesta under Pirgachha upazila functions as a militant training camp, reports our Rangpur correspondent.
Abdul Quddus Khan Salafi, an Afghan War veteran, and another militant leader Abul Kalam Azad had trained a huge number of recruits there. Of the two, Salafi has been detained while Azad is still at large.
Police sources said most of the recruits disguise themselves as madrasa students coming from the adjoining districts.
Superintendent of Police in Rangpur Hasif Aziz this week told The Daily Star, "We are pretty sure that Salafi is an Afghan War veteran. He used to train militants at the Teesta char. A huge number of JMB cadres had received training there."
Our staff correspondent from Bogra adds: Intelligence sources said about a week ago a group of 20 people have entered Bangladesh from across the border to help the JMB execute its plan to launch massive attacks targeting important installations in the north.
The intelligence men could not identify them but learnt that they have fanned out to different areas.
Speaking to the Bogra correspondent over cellphone, a JMB leader said that another group from a neighbouring country arrived in a northern district on Thursday night.
Wishing not to be named, he said that the visiting five-member team would meet the Majlish-e-Shura (top policy-making body) members to finalise a plot to carry out an attack in a bordering district.
The Shura was reconstituted following the arrest of top JMB leader Matin Mehedi in Kurigram in April.
The man on the phone claimed that the militants have planned to blow up all major bridges excepting the Jamuna Bridge. He added that the banned outfit has decided to reduce its dependency on foreign funds by generating income locally. It has already invested a lot of money in brick kilns in districts excepting Sylhet and Chittagong.
He said the JMB is working hand in glove with Harkatul Jihad and an Islami party overtly involved in politics. They plan to divert the attention of the law enforcers through blasts in a southern district and then set off a wave of attacks throughout the northern region.
Our Sirajganj correspondent adds: A top official of the Rab-12 told The Daily Star that they have been alerted to the activities of Islamist militants on outlying chars in the four districts.
Intelligence sources said they believe some of the JMB Shura members are now holed up in Jamalpur and Sirajganj. Some operatives from lower echelons are accompanying them.
Besides, military trainings are well underway at the chars on Brahmaputra near the Jamalpur town. Moinul Humayun Moin, a young Shura member hailing from Shariatpur district, is the main trainer there. He was a student of Jamiul Ulum Madrasa at the city's Mirpur-14.
The sources added that this time a number of elderly men and women have also been inducted into the suicide squad.