A decorated nail from 2100 BC that would have been used to anchor a building's foundations to the ground is shown Thursday in the Netherlands. (Dutch Education, Culture and Science Ministry/Associated Press)

The Dutch government returned 69 artifacts, discovered to have been stolen from Iraq, to Baghdad's ambassador on Thursday.

Dutch Education, Culture and Science Minister Ronald Plasterk said the ancient artifacts were surrendered by Dutch art traders after Interpol and U.S. customs officials traced them to the Netherlands.

Plasterk urged other countries to clamp down on illicit trade in artifacts from the "cradle of civilization," a term used to refer to the former Mesopotamia.

"We should cherish and honour the start of civilization in Iraq and consider it the responsibility of the world to make sure it stays there," he said. "These objects lose a lot of their value if they are stolen from their site."

There was no indication of when the objects, which appear to come from archeological sites in Iraq, were stolen.

Among the artifacts returned were:

• A fragment of a flagstone with an inscription of King Nebuchadnezzar dating from 570 BC.
• Cylindrical stone seals dating from before 2000 BC.
• A terra-cotta relief depicting a bearded man praying.
• A decorated nail from 2100 BC.

Diederik Meijer, an archeologist with the Dutch National Museum for Antiquities, said looting of archeological sites in Iraq appears to be continuing.

He showed an aerial photo of an official archeological dig surrounded by a landscape pockmarked with illegal excavations

Researchers working for UNESCO released a report Wednesday saying the US military in Iraq has damaged parts of ancient Babylon, home of the hanging gardens.

The ruins of the ancient city, more than 4,000 years old, became military "Camp Alpha" after the U.S. invasion in 2003.

The UNESCO report says US troops and contractors dug trenches long through sensitive areas, levelled hilltops and drove heavy vehicles over the fragile paving of once-sacred pathways.

Archeologists noted signs of looting of artifacts in the city, about 90 km south of Baghdad, when the U.S. handed it back to Iraqi authorities in 2004.

UNESCO wants to make Babylon a World Heritage site in an attempt to prevent similar vandalism during wartime.

With files from Associated Press