Newly released surveillance video obtained by CNN shows the chaos and carnage when terrorists armed with assault rifles and grenades stormed an upscale shopping mall in Kenya last month.

More than 60 people were killed in the four-day siege that began Sept. 21 when attackers stormed the Westgate Mall in Nairobi. The Somali-based Islamic terrorist group al-Shabab, which is linked to al Qaeda, claimed responsibility for the attack.

Warning: Graphic Footage - click here if video doesn't display properly