A Frenchman caught up in the Nairobi mall attack who survived by hiding for five hours in his bank said Wednesday he had an overpowering desire to kill the militants when he saw a child's corpse.

The man, who identified himself only by his first name, Eric, said that his initial feelings of helplessness turned to rage when he saw the body and thought it could have been his daughter.

When he came out after being holed up in a secure area at the back of the branch, the sight of the child's body outside the Westgate shopping complex was too much to bear.

"At this moment I thought of my daughter and if I had a pistol I would have killed the terrorists immediately. I wouldn't have thought for a second. I wouldn't have hesitated," he said.

Eric, who heads a company in Kenya, said he and the 20 others were led out by police to safety from the Barclays bank in batches of five.

The attackers were still positioned inside a supermarket opposite the bank, located on the ground floor of the mall, he said, describing the carnage all around.

"It was like a scene from a war," he told FranceInfo radio. "There were cartridges and bodies, shards of glass and blood on the ground," he said. "I couldn't stop myself from seeing it."

"It's at this moment that it became difficult. You feel helpless, you feel you can't do anything, you feel like meat," he said.

Eric had entered his bank at around 11:30 am on Saturday and the attack by Al-Qaeda-linked Al-Shebab militants began minutes later.

He said the bank employees first thought it could be an armed robbery.

But then a man next to him, who said he had retired from Kenya's Special Services, explained it "must be terrorists," as they were using heavy weapons and there was sustained firing.

Eric and the other survivors were led by police to an Indian temple near the shopping complex where they were given food and looked after by volunteers.

It was in the safety of the temple that the enormity of what had happened struck him and the others.

"People started collapsing," he said. "It wasn't a small thing with three people firing in the air."

Eric has since consulted a psychiatrist but says he will not leave Kenya or change his lifestyle even though he does worry for his daughter when she is in school.