Inspector General of Police AKM Shahidul Hoque said all the attackers of Gulshan Holey Artisan café were Bangladeshi citizens.
Of the six, five were certainly militants and law enforcers had been trying to arrest them, he told reporters after attending namaz-e-janeza of the two policemen who are the dead victims among 28 people.
"We had been searching them in different places across the country and now they were killed here," the IGP said at Rajarbagh Police Lines in Dhaka.
Earlier in the day, Prime Minister Sheikh Hasina said six attackers were killed during operation by the law enforcers and another attacker has been captured alive.
In the morning, Inter Services Public Relations (ISPR) directorate of armed forces said 20 bodies were recovered and six armed hostage takers were killed as the military personnel along with members of other regular forces launched an operation to end 10-hour long hostage situation.
At least 30 police officials sustained bullet injuries and two of them - Banani police Officer-in-charge Salauddin and assistant commissioner of police Rabiul Islam - died.
Announcing a two-day state mourning for those killed in Gulshan attack, Prime Minister Sheikh Hasina urged all, including anti-terrorism committees, community police and general people, to get united to resist a handful of derailed terrorists.