The last remains of some of mankind's earliest cities have virtually disappeared through unprecedented looting triggered by the US-led invasion of Iraq, experts said.

Lawlessness and instability have accelerated a process that started in the 1990s but has now reached critical levels, with dozens of archaeological sites plundered to extinction in the past year.

And the presence of US-led troops in one of the world's most glorious ancient capitals has not helped either.

The ancient people of Iraq, often described as the cradle of civilisation, are credited with inventing the wheel, writing and mathematics and developing a culture and history which has resonated through the ages.

"It's one of the major, major trage-

dies around the world. We have basically lost most of the ancient cities of Sumer," said Chicago-based professor McGuire Gibson, referring to one of man's earliest civilisations which dates back to around 3,000 BC.

"There's a culture of looting which has never been on this scale before -- it's totally unprecedented. In this last year we have lost more sites than ever before."

Gibson, who has been visiting Iraq since the 1960s, said an Istanbul conference on the destruction last month was "shocked" by aerial photographs showing the desecration of sites in the months after the invasion.

"Everybody is shocked at what happened. They couldn't believe the pictures we were showing of the damage to the sites," he said, adding that "dozens" of sites had been lost.