NAIROBI, Kenya - The Islamic extremist group that carried out the assault on Nairobi's Westgate Mall says the attackers were part of the group's suicide squad.

Al-Shabab released a propaganda magazine online Tuesday devoted to September's four-day siege on Westgate that killed at least 67 people.

The group said the attackers never expected to make it out alive, rebuffing a claim from a Kenyan police official that the attackers had tried to flee the mall.

Al-Shabab reiterated that it would carry out more attacks in Kenya unless Kenyan troops withdraw from Somalia.

Mall surveillance video shows four gunmen carried out the mall attack. Only two attackers' real names are known so far. Kenyan officials said that the attackers' remains were found in the mall's rubble but no confirmation has yet been made public.