Fred Bosire, who works in the meat section of the supermarket at Nairobi's Westgate shopping mall, was having an ordinary, busy Saturday before the carnage began.

A staffer at the Nakumatt supermarket located in the back of the complex, he was immediately trapped along with hundreds of colleagues and shoppers when gunmen marched in and raked the supermarket aisles with automatic weapons fire.

"I saw people were falling all around me. People crouched behind the meat counter but I squeezed in and got enough room to lie down, face first," Bosire, 35, said from his hospital bed.

Initially he thought it was a robbery -- the kind of thing that residents of the crime-ridden capital are only too familiar with.

"I saw some shoppers still walking around, pushing their shopping carts slowly, trying to figure out what was going on. They, like me, probably thought the gunfire would be short-lived," he said.

The he realised something far more terrifying was going on.

"I didn't think we were the targets, but then I heard the shooters speak. It was hard to make out what they were saying at first because they spoke in a mix of English, Kiswahili and what I think was Arabic. But I knew we were in trouble."

"You have invaded our country, you have raped our women and killed our elderly and it is time we got some retribution," was what he heard.

"I could hear screams, cries for help... they shot those who lay on the ground," Bosire recounted.

He said he heard a woman identify herself and her children as French.

"I knew she had children because they were crying and one of the terrorists told them to shut up. I recall their mother being told: 'You're lucky we don't kill children,' and she was ordered to take her children and run," Bosire told AFP.

He said he then heard another single woman identify herself as French.

"'I have money, take anything you want,' I think I heard her say. But they shot her."

Gunmen pause for drinks

Bosire said his meat counter then came under a barrage of gunfire, and he heard what he described as "the squishy sound of the meat." He later discovered it was the sound of bullets hitting his legs.

"I only later realised I'd been shot, when I started to get cold, when I felt the blood seep through my clothes and when I looked down and saw how the bullets had shredded my trousers. I wanted to cry out, but I knew I couldn't make a sound, that I couldn't move a muscle."

The gunmen then turned their attention to the bottles of wine, whisky and beer lined up on the supermarket shelves. Then he said he passed out.

"When I woke up it was quiet. My throat was parched. I ran my tongue over my lower lip and tried to move but my left leg wouldn't budge. I could feel my phone vibrating -- it was my wife, and thinking I was going to die, I took the risk of picking up," he recalled.

"I remember telling her 'I'm dying, please do not mourn for me,'" he said. He also asked her not to inform their son of his death until after the primary school exams were over next month. "I told her not to call me again, because I was dying."

The gunmen then returned, he said.

"I heard them open what I knew to be the soda fridge when I heard that spurt of gas that's released when you pry open a soda can or bottle," Bosire said, catching a partial glimpse of the killers.

"I could see their feet dangling from the deep freezers when they sat down for what I took to be a break from the killing. There were five pairs of feet. Their hems and shoes were covered in blood."

One of the gunmen was young, he said, describing the tones of a slightly "feminine", unbroken voice.

'The wounded were finished off'

"Before long they started to call out: 'If you're still alive, we'll let you go'. I heard some ladies call out. I wish they hadn't. I wish they'd held on, because I heard them get shot in cold blood."

After hours on the floor drifting in an out of consciousness, Bosire heard Kiswahili being spoken and spotted army boots.

"One of the soldiers was saying that he's never seen so many bodies. He shook my leg to see if I was still alive... I tried to call out but all that came out was a guttural sound. But it was enough," Bosire recounted.

"I don't remember much after that. I remember my leg sticking to the floor. I remember clutching onto the belt of one of the officers who got me out, and I remember the faces swimming when we got out."

Bosire is now in a Nairobi hospital, being treated for bullet wounds to his legs and knees and trying to come to terms with his ordeal.

"I know the president said the nightmare is over, but it isn't for me. I still haven't come to terms with it. It was the worst day of my life."