DHAKA – Bangladeshi investigators have revealed that all of the seven militants involved in the hours-long siege at a Dhaka restaurant on Saturday were Bangladeshi nationals and five of them were listed as terrorists in the country, casting doubts on Middle East-based Islamic State’s claim of responsibility for the attack.

Bangladesh’s national police chief Shahidul Hoque told newsmen that all of the gunmen were local and that the law enforcement agencies had previously conducted multiple raids to arrest five of them who were on the country’s terror watch list.

He further added that the sole attacked in official custody was being interrogated and the findings of his interrogation would be released later on.

The police, however, has still to confirm any possible connection between ISIS and the gunmen.

As many twenty people, including nine Italians, seven Japanese, two Bangladeshis, an Indian and a US  citizen were killed in the unprecedented attack in Bangladesh.

Six of the seven militants involved in the attack were killed by forces while a seventh was captured alive.

The Islamic State militant group had earlier posted online photos of five of the gunmen on Saturday.