DHAKA, Bangladesh (AP) — Security officials in Bangladesh are still trying to piece together events surrounding an attack on a Dhaka restaurant that killed 28 people, including six attackers and 20 hostages. All streets in the area remain blocked.

Bangladesh insists five attackers were from a banned domestic group and that Islamic State has no presence in the country, even though it claims responsibility for the attack.

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.

The attack Friday night was the worst by radical Islamists in the moderate and mostly-Muslim nation of 160 million. Unlike previous attacks, the assailants this time were well-prepared and heavily armed with guns, bombs and sharp objects that police later said were used to torture some of the 35 hostages trapped inside.