Bangladeshi security officers cordon off an area after heavily armed militants attacked a restaurant in Bangladesh's diplomatic zone on Friday night, in Dhaka, Bangladesh. (Photo: AP)

Dhaka: The Bangladesh government is now suspecting the involvement of Pakistan’s spy agency ISI in Friday's deadly terror attack in a restaurant in Dhaka where unknown militants hacked 20 hostages to death.

According to a report in NDTV, HT Imam, who is the political advisor to Bangladesh Prime Minister Sheikh Hasina on Sunday said that the attack seemed to be the handiwork of a local banned terror group called Jamaat-ul-Mujahideen that has links to the Pakistani spy agency.

Read: A timeline of the weekend hostage crisis in Bangladesh

"Pakistan's ISI and Jamaat connection is well known...they want to derail the current government, all victims were hacked to death like Jamaat and local terror groups do," said Imam.

Read: Bangladesh says gunmen behind restaurant killings local, some known

Home Minister Asaduzzaman Khan had earlier ruled out the role of Islamic State in the attack and said the jihadists who slaughtered hostages at the Dhaka restaurant were members of the homegrown Bangladeshi militant outfit named by Imam.

Many details of the attack remain unclear a day after commandos stormed the restaurant and rescued 13 people. But police released photographs of the bodies of five attackers, along with their first names: Akash, Badhon, Bikash, Don and Ripon.

Read: Bangladesh terror attack: Hostages asked to recite verses from Quran

Their families hadn't heard anything from them in months, according to police.

"They are all Bangladeshis. They are from rich families, they have good educational background," Asaduzzaman Khan said.

Read: 20 killed, 6 ISIS terrorists shot dead in Bangladesh hostage crisis

He once again refuted the possibility that the Islamic State could have been behind the attack despite the group claiming responsibility on Saturday and releasing horrifying photographs of what unfolded overnight Friday.

The government insists the extremist Sunni Muslim group has no presence in the country, and in the past has suggested that any claims of responsibility for violence waged in the South Asian country are simply opportunistic attempts at grabbing global attention.