Douglas Wood is recovering from his ordeal in Australia

In his first extensive interview, Douglas Wood, 63, also told Australian TV of his efforts to retain his sanity during his captivity.

The engineer was held for 47 days by gunmen in Baghdad before being rescued by Iraqi forces earlier this month.

He was reportedly paid A$400,000 dollars (US$307,000; �169,000) by Channel Ten for his story.

Mr Wood was bound, gagged, beaten and fed only bread and water by his captors.

'Replay of my life'

He said he heard two Iraqi captives being murdered on successive nights, the first after he had been knocked to the ground just inches from the Australian's feet.

"He collapsed to the ground. His head was maybe two inches from my foot and bang, bang, bang - even a silenced gun is very consciously a gun shot in an enclosed space.

"The next night they came in and there was a television set. They turned up the volume... and then bang and a minute later another bang."

Wood said he felt like a traitor after calling for the withdrawal of troops

Asked how he felt about the killings, Wood replied that he had thought: "When is my turn?"

But he said the low point of his ordeal was when, during a brief period when he was not blindfolded, he saw his two Iraqi assistants led away to their deaths.

"I feel absolutely rotten. I was the ultimate cause of it."

He said he planned to send money to the families of the dead men.

He said his time in captivity was often uneventful but was punctuated by immense fear.

"I think I was conscious of trying to keep myself sane, by exercising my mind - a replay of my life, all the girls I've ever known, try and count them, what were their names...?"

Ransom denial

Mr Wood was found in a house in Baghdad by Iraqi and US soldiers during what one military commander said was a "simple everyday mission".

When his rescuers were breaking in through the front door, Mr Wood said he thought al-Qaeda had come to execute him.

"The fear side of me is thinking maybe bloody al-Qaeda turned up and decided to take over, and that meant cut the throat time."

He also said he felt like a traitor when he was forced at gunpoint to make a video plea for the US and Australia to withdraw their troops from Iraq.

Mr Wood is recovering with his family in Melbourne.

The BBC's Phil Mercer in Sydney says relatives have expressed their worries about his mental health, although he appeared to be bright and spirited during his television interview.

The Australian government has insisted that no ransom was paid to secure Mr Wood's freedom.