The domestic militancy in the country is operated from war-torn Iraq, according to intelligences agency.
This militant organizations use improvised explosive devices (IED) on their instructions, source added,
After law enforcers in Bangladesh carried out anti-militancy operations across the country in 2017 the leaders of militant groups fled the country through land borders to reach Iraq.
At least six attacks on police were carried out in the last nine months.
Investigating agencies told The Daily Observer on Friday that at least 10 to 12 active leaders of militant outfit Neo JMB sent instruction from Iraq.
Militants use different encrypted apps to communicate and share organisational directives, he added.
Two policemen, including a security detail of LGRD Minister Tazul Islam, were injured in the attack when the minister was passing through Dhaka's Science Laboratory area last week.
However, the minister was unhurt in the attack.
Meanwhile, Inspector General of Police (IGP) Mohammad Javed Patwary, in May said militants are targeting law enforcement officials, including police, with an increasing trend of "lone wolf" attacks.
"Militants are now using the 'lone wolf' system all over the world. The trend of lone wolf attacks has gone up compared to that of coordinated attacks and it is almost impossible to stop this trend," he said.
The IGP also claimed that no foreign militant organizations are active in Bangladesh. "Militant organizations like Islamic State (IS) are not active in Bangladesh but they may have communicated their ideology to some people."
Asaduzzaman Mia, Commissioner of Dhaka Metropolitan Police (DMP), said last week police were the target of Science Laboratory crossing bomb blast in Dhaka area on Saturday.
The DMP commissioner said this based on circumstantial evidences of the blast.
The commissioner said police were the target in the last three incidents where bombs were blasted in Gulistan, in Malibagh and recovery of a bomb at a police box in Khejur Bagan near the Jatiya Sangsad Bhaban.
Law enforcers were able to detain several people in connection with the three incidents and investigations are going on, he added.
Middle-East-based militant outfit Islamic State or IS has claimed responsibility for the crude bomb attack on police in Dhaka, terrorism watchdog SITE Intelligence Group said.
The US-based SITE Intelligence said in a tweet on Sunday, "IS claims credit for bomb blast on police in Bangladeshi capital."
SITE Intelligence had previously informed about IS's claim of responsibility of the 2016 terrorist attack on Holey Artisan Bakery in Gulshan as well as another attack on the police in the capital's Gulistan in April this year.
Intelligence officials in Bangladesh, however, have been quick to question the credibility of SITE Intelligence and dismissed the claims of responsibility purportedly made by IS in the past without being able to unravel the cases themselves.
The Police Headquarters believe the attack was perpetrated by domestic terrorists without any ties to IS.
Nevertheless, the authorities will investigate the incident. All units of the police have been put on alert as the blast is believed to have targeted the law enforcers, he added.
