WASHINGTON (Reuters) - A U.S.-led invasion of Iraq could destroy priceless artifacts but also provide an opportunity to save antiquities looted and damaged during a decade of U.N. sanctions, a U.S. archaeologist said on Thursday.

"Measured against human suffering, material items seem less significant, but also under threat is an important part of the world's cultural heritage," McGuire Gibson of the University of Chicago wrote in a commentary in Friday's issue of the journal Science.

The United States launched a war against Iraq on Wednesday to topple Iraqi President Saddam Hussein and rid the country of suspected weapons of mass destruction.

"The archeological wealth of Iraq is tremendous. It would be a tragedy for the entire world if thousands of sites are lost as a result of political upheaval or decisions made for short-term economic gain," Gibson wrote.

"Iraq is ancient Mesopotamia, where the earliest civilization was developed in the fourth millennium B.C.," Gibson said. "Sumerians, Akkadians, Babylonians and Assyrians, as well as Leleucid Greeks, Parthians and Sasanians from Iran, and then Arabs ruled increasingly more complex empires from capitals in this country."

The name Mesopotamia, Greek for "land between the rivers," refers to the Tigris and the Euphrates rivers that run through the region.

Gibson said he and others had briefed Pentagon officials on the ancient sites that could be vulnerable.

"I know that the (U.S.) Army is quite sensitive to sites at this moment," Gibson said in a telephone interview.

"They know that the hills in southern Iraq are 99 percent ancient sites. They also, I know, have put out a standing order that soldiers shouldn't pick up things off sites."

HOPES FOR RESTORING DAMAGED SITES

One threat is if the war drags on and troops have to dig in. They will seek out high ground which, in Iraq, is almost certain to be a mound covering an archaeological site.

Gibson hopes pinpoint bombing can preserve as much as possible. For example, the 12th-century Abbasid Palace backs onto Iraq's Defense Ministry building and was damaged in the 1991 Gulf War.

He also expressed hope Iraq could be reopened to archaeological study.

"The real damage to sites has happened under the (U.N.) embargo of the last 13 years," he said. "There is a need to get the Department of Antiquities back up to operating level."

Many scholars fled Iraq over the past decade because they were unable to make a living, he said.

Gibson, who has worked extensively in the region, hopes international archaeologists would be invited back to Iraq to help survey what is there, restore what has been damaged, and look for new sites.

"The number of archeological sites in Iraq is almost impossible to estimate," he wrote. "There are, as a conservative estimate, probably 25,000 major mounded sites and each of them is surrounded by dozens of small villages and towns."