Transcript for Westgate: Footage Shows Brutal Nairobi Mall Massacre
Now to riveting new pictures inside that mall as ordinary shoppers realized terrorists were descending from the aisles of the stores. It happened in kenya. Brian ross says another threat of an attack on a mall is looming. Reporter: The new video first broadcast by cnn shows the panic as the mall shoppers realized what was happening. And then the callous rampage of the gunman. One victim is shot as he cowers in fear. Others scramble for safety. Only four gunman is seen on the video. E is seen escorting an injured teenager out of the supermarket. At another point, they stop the killing to take turns praying. They're carrying it appears AK-47s. Automatic versions. They're in the middle of shooting people talking on the cell phone. Reporter: U.S. Officials believe the men behind the attack were part of an al qaeda connected group in somalia. U.S. NAVY S.E.A.L.s Unsuccessfully tried to capture the leader one week ago. Now the u.S. Is issuing a warning to americans that the group may be planning another attack in the african country of uganda. We put out the statement because of information available. In terms of the expense I'm not going to outline that. Reporter: Shortly after the attack several said one of the attackers was a woman. But the new video shows only men with guns. Security experts continue to be amazed that four men could hold off kenya police and army forces for almost three full days. In fact, the fbi is now screening news video taken of shoppers fleeing the mall to see if any other attackers were able to slip out during the panic and now could be part of the planning for yet another mall massacre.
This transcript has been automatically generated and may not be 100% accurate.