HATRA, Iraq: Forensic experts digging for evidence against ousted Iraqi leader Saddam Hussein have carried out their first full exhumation of a mass grave filled with the skeletons of scores of women and children, many shot in the back of the head.

"This is all women and children. We have taken in excess of 120 bodies out of there," said U.S. investigator Greg Kehoe as he stood over one of nine trenches piled with bones and scraps of clothes and jewelry near the northern Iraqi town of Hatra.

Among the dead are pregnant women, even a young boy still clutching his ball, whose bodies were ploughed into their earthen tombs by bulldozers.

"This is something in the time I've been doing mass graves I've never seen done before," said Kehoe, a lawyer who has also worked in the Balkans.

The bodies are believed to be those of hundreds of Kurds killed by Saddam's feared regime in a deadly campaign in 1987 and 1988, for which the toppled Iraqi leader is facing trial on charges of crimes against humanity.

"These bodies were just pushed in. It was all women and children. No men. All these people were executed with small arms fire ... (It) includes pregnant woman," said Kehoe.

There are about 40 known mass graves in Iraq containing possibly tens thousands of bodies dumped by Saddam Hussein's regime.

But exhumation has in many cases been a free-for-all, with relatives searching for loved ones in the early days after the fall of Baghdad accidentally destroying or tampering with evidence that could be used against Saddam.

Kehoe and a team of U.S., British and Iraqi forensic experts are now conducting full scientific exhumations to preserve hard evidence, uncovering the ghastly horrors of the old regime.

Saddam, who first appeared before a court in July, faces seven charges including the 1987-88 offensive that saw Kurdish villages razed in northern Iraq and the gassing of the village of Halabja, which left 5,000 people dead.

Kehoe said the Hatra grave was the first to be exhumed according to international standards since his appointment last December, but said his team hopes to work on another 10 sites.

"Were trying to meet international standards that have been accepted by courts throughout the world," Kehoe said. "One woman when she was executed was carrying her two-year old child, shot in the back of the head. She was shot in the face," he said.

The former U.S. prosecutor's voice cracked as he showed slides of some of the victims.

"This is a young boy with a ball, still holding onto the ball when we uncovered him ... This is the little ball he was holding onto, you see his little arm right here, this little ball, this little arm, this little boy." In the end, he hopes to be able to identify the bodies and return them to families.

"Everybody said never again after the Holocaust. The world wasn't listening. That's how it happened again and again and again." He said he thinks often about the piles of children's bones he has seen in the dirt.

"Sometimes, you go in there, you see soldiers, and it's not to justify it, but my God, little babies, women, with their children shot in the back of the head ... Why?"