Nairobi mall attackers may have escaped: NYC police

However, security sources in Kenya said they died in a final stand off with commandos

The four attackers responsible for killing at least 67 people at a Kenyan shopping mall may have escaped due to lax security, according to a New York police report.

The victims aged eight to 78, from 13 different countries, were killed at the Westgate mall in Nairobi during a terrifying assault claimed by Somalia's Al-Qaeda-linked Shebab terror group.

The media speculated the gunmen may have escaped in the chaos of the September fighting, although security sources in Kenya said they died in a final stand off with commandos.

The New York police report said yesterday the last confirmed sighting of the attackers on the mall's CCTV system was on September 22 at 00:54 hours, 12 hours after the start of the attack.

It took Kenya almost four days to declare the mall safe. The day before doing so, Kenyan forces started a fire and collapsed a large part of the mall, the report said.

"It is unknown if the terrorists were killed or escaped the mall. A major contributing factor to this uncertainty was the failure to maintain a secure perimeter around the mall," it said.

The New York conclusions are based on information obtained by its police officers and unclassified open source information.

Interpol is assisting Kenya in trying to identify four bodies suspected of being those of the gunmen. No identification has yet been announced.

The New York report also highlighted poor coordination between the Kenyan police and the army, which saw troops kill one police officer and wound the commander of a police team.

Most of the victims were probably killed in the first hour of the attack when the gunmen engaged in "wholesale killing" of those trying to hide in places like storerooms, the report said.

According to witnesses and CCTV footage, the gunmen did not want to take hostages, only kill a broad spectrum of people.

The New York police report also confirmed a "conscious but erratic attempt" at avoiding Muslim casualties but voiced fears over the possibility of future copycat attacks.

At least one attacker asked some of the victims if they were Muslim, if they answered yes they were asked the name of the Prophet Mohammed's mother. If they didn't know, they were shot.